Make the pretzel dough: In a large bowl, combine water, sugar, and yeast. Stir to combine, and set aside for 5 to 10 minutes, or until the mixture begins to foam on top.
Add the flour, salt, and butter to the yeast mixture. Mix together until you start to get a rough, shaggy dough. Knead the dough for 5 to 10 minutes, adding a bit of flour if it's too sticky, or until the dough is smooth and slightly tacky. (You can do this all by hand or with an electric mixer fitted with the dough hook attachment).
Cover the dough and set aside in a warm place for 45 minutes to 1 hour, or until about doubled in size. Preheat your oven to 400°F. Line 2 large (non-reactive) baking dishes with parchment paper (I used glass bake ware). Set aside.
Uncover your dough, and turn it out onto a lightly floured work surface. Pat the dough down to deflate, then divide into 6 equal portions. Take one piece of dough and roll it into a rope that's about 24 inches long. Curve the dough into a "U" shape, then twist the 2 ends around each other twice. Bring the ends down to the bottom of the "U" and pinch to seal. (See below for video tutorial) Repeat with the remaining portions of dough.
Make the baking soda bath: In a 2 quart (glass or ceramic) baking dish, combine boiling water and baking soda together. Whisk to dissolve the baking soda. While the water is still warm, place the shaped pretzels into the bath and let sit for about 15 seconds on each side.
Remove the pretzels from the baking soda and water mixture, and drain well. Transfer to your prepared baking dishes, leaving a bit of space between each pretzel. Sprinkle salt on top of each pretzel.
Bake in the center of your preheated 400°F oven for 10 to 15 minutes, or until a deep golden brown on top. Cool slightly on the baking sheet before serving.