2tablespoonsboiling water,plus more room temperature water as needed
1cup(2 sticks / 225g) unsalted butter,at room temperature
4cups(520g) powdered sugar,sifted
2teaspoonspure vanilla extract
In a small bowl, whisk together your espresso powder and boiling water to dissolve the coffee. Set aside to cool completely to room temperature before using.
In a large bowl, combine butter and sugar. Using an electric mixer fitted with the beater attachment, mix together on low speed until the sugar is fully dissolved. Crank the speed up to medium and cream together until the mixture has fluffed up and lightened in color (about 2 to 3 minutes).* You can do this by hand, but it's a real workout!
Add in your vanilla extract and cooled espresso mix. Whip together until light and fluffy (another 2 to 3 minutes on medium speed). If needed, add more room temperature water, 1 tablespoon at a time, until you reach a pipe-able consistency.