Name: Chocolate-Peanut Butter Cake
Total time: 4 h 5 min
Ingredients: 1½ cups (7½ ounces/213 grams) all-purpose flour; 1 teaspoon baking soda; ½ teaspoon baking powder; ¼ teaspoon salt; 1¼ cups boiling water; 4 ounces (113 grams) unsweetened chocolate , chopped; ½ cup (1½ ounces/43 grams) Dutch-processed cocoa powder; 1 teaspoon instant espresso powder or instant coffee powder; 10 tablespoons unsalted butter , softened; 1½ cups packed (10½ ounces/298 grams) light brown sugar; 3 large eggs , room temperature; ½ cup sour cream , room temperature; 1 teaspoon vanilla extract; 1 cup (7 ounces/198 grams) sugar; 5 large egg whites; ⅛ teaspoon salt; 28 tablespoons (3½ sticks) unsalted butter , cut into 28 pieces and softened; 1 cup creamy peanut butter; 1¼ teaspoons vanilla extract; 4 ounces (113 grams) bittersweet chocolate , chopped; 4 tablespoons unsalted butter , cut into 4 pieces; 2 tablespoons light corn syrup; ½ cup candied peanuts

Chocolate-Peanut Butter Cake

By America's Test Kitchen

Published on December 11, 2017

Time

1¾ hours, plus 2 hours cooling and 20 minutes setting

Yield

Serves 12

Ingredients

Cake Layers

1½ cups (7½ ounces/213 grams) all-purpose flour 1 teaspoon baking soda ½ teaspoon baking powder ¼ teaspoon salt 1¼ cups boiling water 4 ounces (113 grams) unsweetened chocolate, chopped½ cup (1½ ounces/43 grams) Dutch-processed cocoa powder 1 teaspoon instant espresso powder or instant coffee powder10 tablespoons unsalted butter, softened1½ cups packed (10½ ounces/298 grams) light brown sugar 3 large eggs, room temperature½ cup sour cream, room temperature1 teaspoon vanilla extract

Frosting

1 cup (7 ounces/198 grams) sugar 5 large egg whites ⅛ teaspoon salt 28 tablespoons (3½ sticks) unsalted butter, cut into 28 pieces and softened1 cup creamy peanut butter 1¼ teaspoons vanilla extract

Decoration

4 ounces (113 grams) bittersweet chocolate, chopped4 tablespoons unsalted butter, cut into 4 pieces2 tablespoons light corn syrup ½ cup candied peanuts

Before You Begin

The devil's food-style cake layers are packed with chocolate flavor. For an accurate measurement of boiling water, bring a full kettle of water to a boil and then measure out the desired amount. We like to use our Homemade Candied Peanuts for this recipe, but you can use store-bought peanuts.

Instructions

for the cake layers

Adjust oven rack to middle position and heat oven to 350 degrees. Grease three 8-inch round cake pans, line pans with parchment paper, grease parchment, and flour pans. Whisk flour, baking soda, baking powder, and salt together in bowl. In second bowl, whisk boiling water, chocolate, cocoa, and espresso powder until smooth.

Using stand mixer fitted with paddle, beat butter and sugar on medium-high speed until pale and fluffy, about 3 minutes. Add eggs, one at a time, and beat until combined. Add sour cream and vanilla and mix until incorporated.

Reduce speed to low and add flour mixture in 3 additions, alternating with chocolate mixture in 2 additions, scraping down bowl as needed. Give batter final stir by hand.

Divide batter evenly among prepared pans and smooth tops with rubber spatula. Bake until toothpick inserted in center comes out clean, 15 to 20 minutes, rotating pans halfway through baking.

Let cakes cool in pans on wire rack for 10 minutes. Remove cakes from pans, discarding parchment, and let cool completely on rack, about 2 hours.

for the frosting

Combine sugar, egg whites, and salt in bowl of stand mixer; place bowl over saucepan filled with 1 inch barely simmering water, making sure that water does not touch bottom of bowl. Heat sugar mixture, whisking gently but constantly, until slightly thickened and foamy and mixture registers 150 degrees, about 3 minutes.

Place bowl in stand mixer and fit mixer with whisk attachment. Whip sugar mixture on medium-high speed until consistency of shaving cream, about 5 minutes. Add butter, 1 piece at a time, and whip until fully incorporated, about 3 minutes. (Frosting may look curdled after half of butter has been added; it will smooth out with additional butter.)

Once all butter is added, reduce speed to low and add peanut butter and vanilla; mix until combined, about 30 seconds. Increase speed to medium-high and whip until light and fluffy, about 30 seconds, scraping down whisk and bowl with rubber spatula as needed.

Place 1 cake layer on plate or pedestal. Spread 1 cup buttercream evenly over top, right to edge of cake. Repeat with second cake layer and 1 cup buttercream. Top with third cake layer. Spread remaining buttercream over top and sides of cake.

for the decoration

Microwave chocolate, butter, and corn syrup in bowl at 50 percent power until melted, about 1 minute, stirring with rubber spatula halfway through microwaving. Stir mixture until fully combined and smooth. Let cool until slightly thickened, about 5 minutes. Pour ¼ cup chocolate glaze in center of cake and spread evenly over top with offset spatula. Drizzle ¼ cup glaze along top edge of cake, allowing it to drip down sides. Pour remaining glaze over top of cake and smooth into even layer with offset spatula. Arrange 10 (1-tablespoon) clusters of candied peanuts around top edge of cake, evenly spaced. Let sit until glaze sets, about 20 minutes. Serve.