You know the bad thing about chocolate? When it’s sweetened too much, it loses its subtle, bitter notes, those reminiscent of dark coffee, toffee, or toasted nuts. To remedy that problem, we used only unsweetened chocolate in the batter for this sheet cake. Then we added milk chocolate chips for a sweet finish. Oh, and we added lots of malt, too, even in the frosting. We wanted its nutty, wheaty sweetness to go head-to-head with all that chocolate.
For the cake
10 tablespoons (1¼ sticks) unsalted butter, cut into small chunks, plus additional for the sheet pan
5 ounces unsweetened chocolate, chopped
3 cups all-purpose flour
2 teaspoons baking powder
½ teaspoon salt
1½ cups whole or 2% milk
1 cup plus 2 tablespoons malted milk powder
3 large eggs, at room temperature
1½ cups granulated white sugar
2 teaspoons vanilla extract
12 ounces milk chocolate chips
1. Position the rack in the center of the oven. Heat the oven to 350°F. Generously butter the inside of a 13 × 18-inch lipped sheet pan.
2. Place the butter and chocolate in a medium saucepan set over low heat. Stir until about three-quarters of the chocolate has melted. Remove the pan from the heat and continue stirring until smooth. Cool for 20 minutes.
3. Whisk the flour, baking powder, and salt in a medium bowl until uniform. Whisk the milk and malted milk powder in a second medium bowl until the powder dissolves.
4. Using a handheld electric mixer or a stand mixer with the whisk attachment, beat the eggs and sugar in a large bowl at medium speed until you can make wide ribbons. (The mixture will almost double in volume.) Beat in the cooled butter mixture and the vanilla until smooth.
5. Turn off the mixer and pour the flour mixture evenly over the batter. Beating at low speed, slowly pour in the milk mixture; continue beating until there are no bits of dry flour in the batter. Add the chocolate chips and beat just until evenly distributed. Using an offset spatula, spread the thick batter evenly into the prepared pan.
6. Bake until firm to the touch, and until a toothpick or cake tester inserted into the center of the cake comes out clean, 20 to 24 minutes. Cool in the pan on a wire rack to room temperature, about 1½ hours.
For the buttercream
24 tablespoons (3 sticks) unsalted butter, softened to room temperature
¾ cup malted milk powder
2 tablespoons heavy cream
2 teaspoons vanilla extract
2 to 3 cups confectioners’ sugar
2 cups malted milk balls, crushed, for topping
1. Using a handheld electric mixer or a stand mixer with the whisk attachment, beat the butter and malted milk powder in a large bowl at medium speed until creamy and light, about 2 minutes. Beat in the cream and vanilla until smooth.
2. Turn off the mixer and add 2 cups of the confectioners’ sugar. Beat at low speed until smooth; then beat at medium speed, adding more confectioners’ sugar in ¼-cup increments, until the frosting is spreadable and can hold its shape on the side of a spatula. Using an offset spatula, spread and smooth the frosting evenly over the cooled cake. Sprinkle the crushed malted milk balls on top before serving.
TESTER NOTES
Use malted milk powder, not diastatic malt powder.