Ingredients
Softened unsalted butter, for pans
1 1/2 cups unbleached all-purpose flour, plus more for pans
1 1/2 cups sugar
3/4 cup Dutch-process cocoa powder
3/4 teaspoon baking powder
3/4 teaspoon baking soda
1 1/4 teaspoons kosher salt (we use Diamond Crystal)
2 large eggs, room temperature
3/4 cup low-fat buttermilk, room temperature
3/4 cup hot tap water
2 teaspoons pure vanilla extract
6 tablespoons vegetable oil
Chocolate Frosting for One-Bowl Chocolate Cake
Preparation
Preheat oven to 350°F. Butter two 8-by-2-inch round cake pans; dust with flour, tapping out excess. In a large bowl, whisk together flour, sugar, cocoa, baking powder, baking soda, and salt. Whisk in eggs, buttermilk, water, vanilla, and oil.
Divide batter evenly between prepared pans. Bake until tops spring back when lightly pressed, about 30 minutes. Transfer pans to a wire rack; let cool 15 minutes. Invert cakes onto rack, remove parchment, then turn top-side up (to prevent sticky tops from sticking to rack); let cool completely.
Spread 1 1/2 cups frosting over top of one cooled cake layer. Top with remaining layer. Spread a thin coat (about 1 cup) of frosting over top and sides of cake to create a “crumb coat.” Refrigerate about 20 minutes, then frost top and sides of cake with remaining frosting. (For a more refined look, trim domed top of cake flat before layering and frosting.)
