YELLOW BUTTER CAKE WITH CHOCOLATE FROSTING

Steps:

• Preheat the oven to 350°F. Butter two 9-by-2-inch round cake pans; line the bottoms with parchment paper. Butter parchment, and dust with flour, tapping out excess; set aside. Into a medium bowl, sift together flours, baking powder, and salt; set aside.
• In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and sugar until light and fluffy, 3 to 4 minutes, scraping down the sides of the bowl as needed. Beat in eggs, one at a time, then beat in vanilla. With the mixer on low speed, add the flour mixture in three parts, alternating with the milk and beginning and ending with the flour; beat until combined after each addition.
• Divide the batter between the prepared pans, and smooth with an offset spatula. Bake rotating the pans halfway through, until cakes are golden brown and a cake tester inserted in the centers comes out clean, 30 to 35 minutes. Transfer pans to a wire rack to cool 20 minutes. Invert cakes onto the rack; peel off the parchment. Reinvert cakes and let them cool completely, top sides up.
• Using a serrated knife, trim the tops of the cakes to make level. Place one layer on a cake plate, and spread top with 3/4 cup Dark Chocolate Frosting. Place the other cake layer on top. Spread the entire cake with remaining frosting, swirling to coat in a decorative fashion. Cake can be kept in the refrigerator, covered with a cake dome, for up to 3 days. Let cake sit at room temperature for 20 minutes before serving.
• Line two standard 12-cup muffin pans with paper liners; set aside. Follow instructions for Yellow Butter Cake, dividing the batter evenly among the prepared cups so that each is about two-thirds full. Bake, rotating pans halfway through, until cupcakes are golden brown and a cake tester inserted in the center of a cupcake comes out clean, about 20 minutes. Transfer pans to a wire rack to cool. Invert cupcakes onto the rack; reinvert and let cool completely, top sides up. Spread about 1/4 cup frosting on top of each cupcake. They can be kept in an airtight container at room temperature for up to 3 days. Makes 2 dozen.