American-Style Chocolate Buttercream Recipe

Name: American-Style Chocolate Buttercream Recipe
Total time: 45 min
Yield: 24
Ingredients: 4 ounces heavy cream (about 1/2 cup; 115g), straight from the fridge; 4 ounces finely chopped dark chocolate (not chips), around 72% (about 2/3 cup; 115g); 12 ounces unsalted butter (3 sticks; 340g), softened to about 65°F (18°C); 9 ounces organic powdered sugar (about 2 1/4 cups, spooned; 255g), preferably tapioca-based, such as Wholesome (see note); 3 ounces high-fat Dutch cocoa powder (about 1 cup, spooned; 85g); 2 teaspoons vanilla extract, plus more to taste; 3/4 teaspoon (3g) Diamond Crystal kosher salt, plus more to taste; for table salt, use about half as much by volume or the same weight; 3/4 teaspoon instant espresso powder, plus more to taste