This rich and decadent chocolate mousse cake is as delicious as it is impressive. The cake is so SO soft and moist (even after sitting in the fridge!) and is adapted from this reader favorite chocolate cake recipe. The mousse is made without raw eggs and without gelatin - but still sets up to a perfectly sliceable and airy texture!
the cake components
This cake features 3 deliciously rich and decadent chocolate layers, each with their own texture, flavor, and color!
- Chocolate cake: This is a scaled down version of my absolute favorite chocolate cake recipe! One little tweak I also made was add a hint of black cocoa powder to give it a darker color which I think contrasts so beautifully against the lighter colored mousse. We're not using any butter in the cake because butter can harden and make the cake feel kind of dry as it sits in the fridge for the mousse to set. This oil based cake makes for a soft, spongy, and super moist slice of cake!
- Chocolate mousse: Lightly, fluffy, and tastes like it came from a million dollar restaurant. This chocolate mousse isn't exactly traditional in terms of how it's made, but it sure looks and tastes traditional! It holds it's shape perfectly for sharp and clean cuts but it's light and airy and just melts in your mouth.
- Chocolate ganache: To really drive home that chocolate flavor, this cake is finished off with a silky and smooth ganache on top. It makes the whole thing feel a little extra special. You can also top it with some whipped cream if you'd like!
how to pasteurize eggs for chocolate mousse
It sounds complicated, but it's actually really easy to pasteurize eggs at home! Pasteurization is simply the process of heating (in this case, eggs) to eliminate harmful bacteria. While most traditional mousse recipes use raw egg yolks for richness and whipped egg whites for air, this recipe uses heat treated egg yolks and whipped cream instead.
To heat / pasteurize the egg yolks, we'll be using a double boiler: which is basically just a bowl sitting on top of a pot of simmering water. The egg yolks are added into this bowl then slowly and gently heated to kill off any harmful bacteria and make them safe to eat. You can't heat the eggs in just a standard pan that's placed directly on the heat - the heat would be too harsh and would scramble the eggs. Using a double boiler ensures you have a smooth and creamy mixture.
how to set up a double boiler
A double boiler (also known as a bain-marie) is basically just a bowl set on top of a pot filled with very gently simmering water. It's typically used for things like cooking egg yolks or melting chocolate because it offers a more gentle heat (as opposed to cooking something in a pot over direct heat). If you were to try to cook this egg mixture right in the pot, it would most likely curdle, clump, and leave you with scrambled eggs! When it comes to actually preparing the double boiler, here's how to do it:
- Pick out your pot + bowl. You'll need a bowl that can sit on top of the pot with about 2 to 3 inches of distance between the bottom of the pot and the bottom of the bowl.
- Fill the pot with about 1 inch of water. Set the pot on medium low heat and warm until the edges of the water are lightly bubbly and it's steaming. Adjust the heat as needed to ensure the water doesn't boil (otherwise, again, this can be too harsh of a heat and scramble the egg yolks).
- Whisk together egg yolks and sugar in the bowl then place the bowl over your pot of barely simmering water. Cook the egg yolks over the double boiler, whisking constantly, until the sugar has dissolved, the egg mixture has thickened, and it reaches a temperature of 160°F.
how to make chocolate mousse cake
Make the chocolate cake:
1. Whisk together dry ingredients for the cake.
2. Add in the wet ingredients (minus the hot water) and whisk until smooth.
3. Whisk together boiling hot water and espresso (if using). Pour the hot coffee on top of the cake batter and whisk until combined. The batter will be very loose!
4. Bake the cake and then cool completely to room temperature. Once cooled, use a cake leveler or a sharp serrated knife to level off the top of the cake if it domed while baking. You can skip this step of leveling the cake if you'd like, but the cake slices will appear slightly more rounded.
5. Prep the pan. Line the bottom of a springform pan with parchment paper. Take a long strip of cake collar or parchment paper and line the sides of the pan. Drop the leveled cake into the bottom of the pan and set aside to prep the mousse.
Make the chocolate mousse:
1. Heat treat egg yolks and sugar. See above for a full breakdown of how to set up the double boiler for the egg yolks. The mixture is ready once it's thickened enough to draw a figure 8 in the mixture without it disappearing right away. Take the bowl off the pot of simmering water and place on a wire rack or tea towel.
2. Add vanilla and chopped chocolate. Don't mix together (or the mixture can clump together). Just let the chocolate sit and start to melt from the heat of the egg yolks while you warm the cream.
3. Heat some of the heavy cream until the edges just start to bubble. Do not boil the cream or it may shock the chocolate and cause it to seize.
4. Pour the warm cream over the chocolate and egg yolk mixture. Whisk together until smooth. If you have any little bits of chocolate that haven't melted, you can place the bowl back onto your double boiler to warm the mixture until fully smooth.
5. Cool the chocolate mixture until it's no longer warm and it's about room temperature or slightly cooler.
6. In a separate bowl, whip the remaining cream until it reaches stiff peaks.
7. Fold the whipped cream into the room temperature chocolate mixture. Do this in thirds to gradually loosen up the chocolate mixture. The whipped cream will deflate a bit - that's normal - but take care not to overmix or the mousse will not be quite as airy. Just mix until the streaks of whipped cream barely disappear.
8. Pour the mousse into your pan over the cake. Spread it into an even layer.
9. Chill until firm then make the ganache. To make the ganache, simply melt together chocolate and heavy cream until smooth and pourable.
10. Unlatch the springform pan and remove the cake. Peel off the parchment paper or cake collar from the sides of the cake. Transfer the chilled cake to your serving plate and pour the ganache on top. Chill the cake for about 5 to 10 minutes or until the ganache sets before slicing!
tips for velvety smooth chocolate mousse
- whisk the egg yolk mixture constantly: This helps ensure even heating and prevents clumps!
- use good quality chocolate: A mousse is only as good as the chocolate in it, which is why this is one of those recipes that I recommend reaching for the good stuff. It doesn't have to be the most expensive chocolate on the shelf though! Look for chocolate that's labelled "Baker's" or "couverture" as this is the best chocolate for melting. Avoid chocolate chips because some brands coat the chips to help them keep their shape - which can cause the mousse the feel gritty and grainy.
- cool the chocolate mixture: It's important to allow the chocolate mixture to cool completely to room temperature before folding in the whipped cream. If the chocolate mixture is even slightly warm, it will cause the whipped cream to deflate and will make the mousse dense and watery.
- fold the cream in gradually: If you try to add the whipped cream all at once, it won't incorporate quite as smoothly (because of the difference of weight / texture between the soft cream and the firmer chocolate mixture). The cream will also be more likely to deflate because of how much mixing would be required to incorporate it. Adding it in thirds gradually softens the chocolate and makes for an airier mousse.
more tips for the best chocolate mousse cake
- sift the black cocoa powder: I say this any time black cocoa is involved in a recipe! Black cocoa powder LOVES to clump, so I always recommend sifting it before using.
- don't overmix the cake batter: It'll overwork the gluten and can cause the cake to come out dense and dry!
- use boiling water: Adding hot water to chocolate cake helps "bloom" the cocoa powder which brings out the chocolate flavor! It also melts the batter ingredients slightly to give the cake a smoother texture.
- optional: espresso powder: Adding a hint of coffee to chocolate cake will NOT make it taste like coffee. But the espresso will make the cake taste richer and extra chocolatey!
FAQs
Do I have to use black cocoa powder?
No, you can leave it out! I like using a little bit of black cocoa mostly for the color and the slightly richer flavor, but this cake is just as delicious without it. If you do leave it out, replace it with an equal amount of unsweetened cocoa powder (for a total of ½ cup (40g) unsweetened cocoa powder).
Can I use other types of chocolate for the mousse / ganache?
This recipe works well with semi-sweet or dark chocolate (or a mix of the two). Just keep in mind that the more dark chocolate you add, the more bitter the final cake will be. White chocolate has a slightly different composition, so it may not work in this recipe - although I haven't personally tried it.
Do I need a springform pan?
I highly recommend using a springform pan for layering the cake and mousse just because it is a lot easier to get the cake out. But that being said, you could use a regular cake pan, it'll just be a bit trickier to pull it out. You could also just slice and serve the cake straight out of the pan like a tiramisu.
Can I make chocolate mousse cake ahead?
Because it needs a few hours to chill in the fridge to set, this is a really great make ahead cake for gatherings and special occasions like Christmas, Thanksgiving, and New Year's! This cake can be kept in the fridge for up to 5 days.
How do I store chocolate mousse cake?
Chocolate mousse cake should be kept in the fridge until right before you plan on serving it to ensure the mousse remains firm and sliceable. The mousse will start to soften if it sits out at room temperature for more than about 20 minutes (depending on how warm your home is). Keep stored in an airtight container in the fridge for up to 5 days.
Can I freeze chocolate mousse cake?
Yes! Keep the cake in an airtight freezer container and freeze for up to 2 months. Let the cake defrost in the fridge overnight or on the counter for about 1 hour before serving. Return any leftovers to the fridge until ready to serve.
check out these other recipes!
• Chocolate Peanut Butter Fudge Bars
• BEST Vanilla Cupcakes
• Brown Butter Brownies
• Biscoff Cheesecake
Lastly, if you made this or any of my recipes, be sure to leave a comment and review below! I love hearing your thoughts! Also tag me on Instagram @eatsdelightfulblog so I can see what you're making.
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Chocolate Mousse Cake
- Total Time: 1 hour 10 minutes + 4 hour chill
- Yield: 1 (9") cake
Description
This rich and decadent chocolate mousse cake is as delicious as it is impressive. The cake is so SO soft and moist (even after sitting in the fridge!) and is adapted from this reader favorite chocolate cake recipe. The mousse is made without raw eggs and without gelatin - but still sets up to a perfectly sliceable and airy texture!
Ingredients
For the chocolate cake:
- 1 cup (130g) all-purpose flour, spooned and leveled
- ¾ cup (150g) granulated sugar
- ¼ cup (20g) unsweetened cocoa powder
- ¼ cup (20g) black cocoa powder, sifted*
- 1 teaspoon baking powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- 1 large egg
- ½ cup (120mL) whole milk
- ¼ cup (60mL) vegetable oil, or any neutral flavored oil
- 1 teaspoon pure vanilla extract
- ½ cup (120mL) boiling water
- 1 teaspoon instant espresso powder (optional)**
For the chocolate mousse:
- 4 large egg yolks
- ⅓ cup (70g) granulated sugar
- pinch of salt
- 2 teaspoons pure vanilla extract
- 12 ounces (340g) good quality semi-sweet chocolate, finely chopped***
- 2 cups (480mL) cold heavy whipping cream, divided
For the ganache:
- 4 ounces (115g) good quality semi-sweet chocolate, finely chopped
- ½ cup (120mL) heavy whipping cream
Instructions
Make the chocolate cake:
- Preheat your oven to 350F. Butter a 9 inch springform pan and line the bottom with parchment paper. Set aside.
- In a large bowl, combine flour, sugar, unsweetened cocoa powder, black cocoa powder, baking powder, baking soda, and salt. Whisk to combine.
- 1 cup (130g) all-purpose flour, ¾ cup (150g) granulated sugar, ¼ cup (20g) unsweetened cocoa powder, ¼ cup (20g) black cocoa powder, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt
- Add the egg, milk, oil, and vanilla to the dry ingredients and whisk together until streak free. Take care not to overmix!
- 1 large egg, ½ cup (120mL) whole milk, ¼ cup (60mL) vegetable oil, 1 teaspoon pure vanilla extract
- In a measuring cup, dissolve espresso powder (if using) in hot water. Pour the hot coffee over the cake batter and whisk until combined. Again, take care not to overmix. The batter will be very watery.
- ½ cup (120mL) boiling water, 1 teaspoon instant espresso powder
- Pour the batter into your prepared cake pan and bake in the center of your preheated oven for 20 to 25 minutes or until a skewer inserted into the center comes out clean.
- Cool the cake in your pan for about 10 minutes then flip onto a wire rack and set aside to cool completely to room temperature. Once cooled, take a cake leveler or a sharp serrated knife and level the top of the cake.
- Clean any stuck on cake off of the springform pan, and line the bottom with a fresh piece of parchment paper. Line the sides of the pan with a long strip of cake collar or parchment paper (see above post for visual). Drop the leveled cake into the bottom of the pan and set aside.
Make the chocolate mousse:
- Prepare a double boiler: Pick out a medium heat safe bowl and a pot - the bowl should be able to sit in the pot with about 2 to 3 inches of distance between the bottom of the pot and the bottom of the bowl. See above post for a photo.
- Fill the pot with about 1 inch of water. Place on medium low heat and warm until the edges just barely start to simmer. Adjust the heat as needed to keep the water at a very gentle simmer.
- In the bowl, combine egg yolks and sugar. Whisk to combine.
- 4 large egg yolks, ⅓ cup (70g) granulated sugar
- Place the bowl on top of the pot of barely simmering water - the surface of the water should not be touching the bottom of the bowl.
- Heat the egg yolks over the double boiler for about 10 minutes, while whisking constantly, or until the sugar dissolves and the mixture thickens. You should also be able to pick up some of the mixture with your whisk and draw a figure 8 without it sinking back in immediately.
* To test that the eggs have heated to a safe temperature, the mixture should read 160°F on an instant thermometer. If it hasn't reached this temperature, keep heating the eggs until it does.
- Use a towel or oven mitts to carefully lift and move the bowl off the pot and onto a wire rack. Whisk in the salt and vanilla.
- pinch of salt, 2 teaspoons pure vanilla extract
- Add the chopped chocolate to the bowl, but do not whisk it in. Just let it sit and begin to melt while you heat the cream.
- 12 ounces (340g) good quality semi-sweet chocolate
- Pour ⅔ cup of heavy cream into a pot (you can dump the water out and use the same pot used for the double boiler). Warm the cream until it starts to steam and bubbles around the edges, but do not boil.
- ⅔ cup (160mL) heavy whipping cream
- Pour the hot cream on top of the chocolate and egg yolk mixture. Whisk together until melted and smooth. Everything should easily melt together, but if you have any stubborn little bits of chocolate that aren't melting, you can heat it in 10 second bursts in the microwave (pausing after each burst to whisk) or over a double boiler (while whisking constantly) until melted.
- Set aside the chocolate mixture until it has fully cooled to room temperature. If it's even a little bit warm, the mousse will not whip up properly. You can speed this up by popping it into the fridge, but in that case, I'd recommend whisking it every 10 minutes to ensure it cools evenly.
- In a separate bowl, use an electric mixer fitted with the whisk attachment to whip the remaining 1 & ⅓ cups cold heavy cream until it reaches stiff peaks. To test for stiff peaks, dip your beater into the cream, lift it up and flip it over. The tip of the cream on the whisk should not curl over. Take care not to overwhip the cream or you'll end up making butter!
- 1 & ⅓ cups (320mL) cold heavy whipping cream
- Scoop out about ⅓ of the whipped cream and drop it into the cooled chocolate mixture. Fold it together until more or less combined. A few streaks are fine, but take care not to overmix or the cream will deflate. Fold in another ⅓ of the whipped cream - again some streaks are fine.
- Fold in the remaining ⅓ of the whipped cream, this time until it's streak free. Again, take care not to overmix!
- Pour the chocolate mousse into your pan over the cake. Use a spoon or spatula to smoothen out the top.
- Chill the layered mousse cake for at least 4 hours to allow the mousse to set.
Make the ganache:
- Place the chopped chocolate for the ganache in a medium sized bowl and set aside.
- 4 ounces (115g) good quality semi-sweet chocolate
- In a saucepot, heat heavy cream over medium heat until the edges are bubbly but do not boil.
- ½ cup (120mL) heavy whipping cream
- Pour the hot heavy cream over the chopped chocolate and let sit for about 5 minutes to melt the chocolate slightly.
- Whisk the mixture until fully melted and smooth. If the ganache is hot, place it in the fridge for about 5 to 10 minutes or until cooled slightly before using. It's ok if it's warm, it just shouldn't be super hot.
- Take the chilled cake out of the fridge and unmold it from the pan. Peel off the cake collar / parchment paper from the side and place the cake on your serving dish.
- Pour the ganache on top and spread into an even layer. Place the cake back in the fridge for about 5 to 10 minutes to set the ganache before slicing and serving!
Notes
* Black cocoa powder helps darken the cake and gives it a richer flavor. I highly recommend sifting black cocoa powder before using in any recipe because it tends to clump more than unsweetened cocoa. You can leave out the black cocoa powder if you prefer - the cake will just be a bit more reddish brown colored but equally delicious! If you don't use black cocoa, replace it with an equal amount of unsweetened cocoa powder (so for a total of ½ cup (40g) unsweetened cocoa powder in the cake).
** Adding a hint of instant coffee to the cake batter will make it taste even richer and chocolatier! The coffee won't make the cake taste like coffee, but if you prefer, you can leave it out!
*** This is a recipe that I would recommend splurging a little bit extra on the chocolate because it will make a difference in texture and flavor! The best chocolate for melting is Baker's or couverture chocolate - they melt smoothly and have the best flavor. You don't need to buy the most expensive stuff on the shelf though! An off brand bar of chocolate usually works just as well as the pricier stuff. Avoid using plain chocolate chips as some brands have a special coating added to help the chips keep their shape when heated (which can result in a clumpy and grainy mousse!)
- Prep Time: 40 minutes
- Bake Time: 20 minutes
- Cook Time: 10 minutes
- Category: Cakes
Enjoy!
Hina says
Can i make the mousse a day before and bake the cake next day
Missy says
Best chocolate cake I've ever had! I felt like the mouse was a little heavy...I would add more cream and/or use the whites next time. I could've just ate the cake itself and been happy! I'm old and I've made a lot of cakes ...this is the best! I didn't deviate from the recipe at all and I did use black cocoa powder! That cake is easy and phenomenal!!!!!
Shelby says
Thank you for making every step of the recipe clear and easy to follow! Even though I'm a big baker, I had never made mousse before but THIS RECIPE TURNED OUT PERFECT! Every person that tried it absolutely loved it, with one asking me to make it again for her birthday coming up.
Quick note: I only had a 10in springform pan, but it still worked out great. I still baked it at the same temperature.
Therese says
I used my own chocolate cake recipe for the bottom layer and used Mimi’s mousse and ganache. The mousse and ganache was delicious and would use this recipe again. It was a big hit at my dad’s birthday party!
Laurie says
I would like to make this but we have a few gluten free people in the family. Do you think that I could swap out the flour for King Arthur 1 to 1 gluten free flour? Please let me know! I’m not very experienced with gluten freeThank you!,
Edda Magaway says
Hi, if my springform pan is 27cm, how much do I need to add toadjust the recipe?
Ariane Bourgon says
Can you make this ahead and freeze it?
Alyssa says
How important is a spring form pan for this? I don't have one and don't want to buy one for one recipe
Mimi says
The springform pan just makes it easier to pull the cake out and onto a serving board, but here are some alternative options!
1) You could use a regular high sided cake pan if you prefer - it'll just be a bit trickier to get it out. I would cut 2 long strips of parchment paper (long enough to run along the bottom of the pan and go up and over the sides). Form an X shape with the strips and lay them into the bottom and over the sides of your pan - this will give you "handles" to pull the cake out. Then cover the bottom of the pan with a parchment paper round and cover the sides with a long strip of cake collar or parchment paper. Layer the cake and mousse on top and chill until firm before pulling it out!
2) Layer the cake directly on your serving plate. To do this, lay the cake down on the serving plate, then encircle it with the cake collar and tape the ends to hold them in place. Cake collar is preferable because it's more sturdy, but you could also do this with parchment paper - you just may need 2 or 3 layers to make it strong enough. Make sure it's about 3 to 4 inches high, and then spread the mousse on top and chill until firm before peeling off the collar / parchment.
3) Simply slice and serve the cake straight out of the pan!
I hope that helps! ❤️