This recipe is extremely versatile. We love to use it for cupcakes, but it makes an equally impressive layer or sheet cake; either is a perfect choice for kids’ birthday parties, swirled with Swiss Meringue Buttercream. For a more grown-up flavor, try icing the cupcakes with Mocha Buttercream (page 213).

　　

Ingredients

makes 2 dozen

　　2 1/2 cups all-purpose flour

　　1 1/4 cups Dutch-process cocoa powder

　　2 1/2 cups sugar

　　2 1/2 teaspoons baking soda

　　1 1/4 teaspoons baking powder

　　1 1/4 teaspoons salt

　　2 large whole eggs, plus 1 large egg yolk

　　1 1/4 cups milk

　　1/2 cup plus 2 tablespoons vegetable oil

　　1 1/4 teaspoons pure vanilla extract

　　1 1/4 cups warm water

　　Swiss Meringue Buttercream (page 386)

　　Chocolate Curls, for garnish (page 395; optional)

　　

Step 1

Preheat the oven to 350°F. Line two standard 12-cup muffin pans with paper liners. Into the bowl of an electric mixer, sift together flour, cocoa, sugar, baking soda, baking powder, and salt. Attach bowl to mixer fitted with the paddle attachment; add the eggs and yolk, the milk, oil, vanilla, and warm water. Beat on low speed until smooth and combined, about 3 minutes; scrape down the sides of the bowl as needed.

　　

Step 2

Divide batter evenly among the muffin cups, filling each about two-thirds full. Bake, rotating pans halfway through, until a cake tester inserted in the center of a cupcake comes out clean, 20 to 25 minutes. Transfer pans to a wire rack to cool slightly. Invert cupcakes onto the rack; then reinvert and let them cool completely, top sides up. Frost cupcakes with Swiss Meringue Buttercream, swirling to cover, and garnish with Chocolate Curls. Cupcakes can be refrigerated in an airtight container for up to 3 days.

　　

Layer Cake Variation

Step 3

Coat two 8-by-2-inch round cake pans with nonstick cooking spray. Line bottoms with parchment paper; spray parchment. Set aside. Follow instructions for One-Bowl Chocolate Cupcakes, dividing batter between the prepared pans. Bake, rotating pans halfway through, until a cake tester inserted in the centers comes out clean, about 45 minutes. Transfer pans to a wire rack to cool 30 minutes. Invert cakes onto the rack; peel off the parchment. Reinvert cakes, and let them cool completely, top sides up.

　　

Step 4

Using a serrated knife, trim the tops of the cake layers to make level. Place one layer on a cake plate, and spread 2/3 cup buttercream on top. Place other cake layer on top. Spread entire cake with remaining buttercream, swirling to cover completely.

　　

Sheet Cake Variation

Step 5

Butter a 13-by-9-inch pan and dust with cocoa powder, tapping out excess. Follow instructions for One-Bowl Chocolate Cupcakes, transferring batter to the prepared pan. Bake, rotating pan halfway through, until a cake tester inserted in the center comes out clean, 45 to 50 minutes. Frost as desired.

　　Reprinted with permission from Martha Stewart's Baking Handbook by Martha Stewart. © 2005 Clarkson Potter