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brooklyn blackout cake

Brooklyn Blackout Cake

A twist on the legendary three-layer devil’s food cake. We’ve swapped out the chocolate pudding cake layer filling for chocolate mousse. Our cake is flavored with bittersweet chocolate, unsweetened and black cocoa powders; filled with chocolate mousse, and frosted with black cocoa powder buttercream. A layer of dark chocolate cake crumbs covers the cakes exterior.
Prep Time 30 mins
Cook Time 1 hr 45 mins
Total Time 2 hrs 15 mins
Course Dessert
Cuisine American
Servings 8

Equipment

  • Three 6-inch round cake pans OR three 8-inch round cake pans

Ingredients
  

Cake:

  • 84 grams bittersweet chocolate, finely chopped (3 ounces)
  • 180 grams boiling water (3/4 cup)
  • 3 grams instant espresso powder (1 tablespoon)
  • 256 grams all-purpose flour (2 cups)
  • 60 grams unsweetened cocoa powder (1/2 cup)
  • 30 grams unsweetened black cocoa powder (1/4 cup)
  • 5 grams baking soda (1 teaspoon)
  • 4 grams baking powder (3/4 teaspoon)
  • 3 grams fine sea salt (3/4 teaspoon)
  • 5 grams vanilla bean paste or pure vanilla extract (1 teaspoon)
  • 170 grams unsalted butter, softened (3/4 cup OR 1-1/2 sticks)
  • 200 grams packed brown sugar (1 cup)
  • 100 grams granulated sugar (1/2 cup)
  • 200 grams egg (4 large)
  • 60 grams egg yolk (2 large)
  • 180 grams whole milk (3/4 cup)

Chocolate Mousse:

  • 85 grams bittersweet chocolate (1/2 cup), finely chopped
  • 100 grams egg whites (3 or 4 large)
  • 50 grams granulated sugar (1/4 cup)
  • 210 grams heavy whipping cream (3/4 cup + 2 tablespoons), cold

Black Cocoa Buttercream:

  • 113 grams unsalted butter (1/2 cup OR 1 stick)
  • 250 grams powdered sugar (2 cups)
  • 42 grams black cocoa powder (3 tablespoons)
  • 42 grams heavy cream or whole milk (3 tablespoons)

Instructions
 

Cake:

  • Preheat oven to 350 degrees F. Butter and line bottoms of three 6-inch cake pans with parchment paper rounds.
  • Add the chopped bittersweet chocolate and espresso powder to a small bowl. Pour boiling water over chocolate. Let set for 5 minutes. Stir to ensure chocolate has melted. Set aside to cool.
  • Sift the all-purpose flour, unsweetened cocoa powder, black cocoa powder, baking soda, baking powder, and fine sea salt into a large mixing bowl. Set aside.
  • Add the unsalted butter to stand mixer bowl. Using paddle attachment beat butter on medium speed 2 minutes. Add the light brown sugar and granulated sugar to the stand mixer bowl. Beat on medium speed 2 minutes, or until light and fluffy.
  • Add the eggs and yolks to the stand mixer bowl, one at a time. Beat on low speed after each addition, for about 30 seconds or until fully incorporated.
  • Add half the flour mixture to the stand mixer and beat on low just until incorporated. With the motor running, stream in the whole milk. Stop the mixer and add the remaining flour mixture. Beat on low just until incorporated.
  • Add the chocolate espresso mixture and beat on low until incorporated.
  • Divide the cake batter evenly between the three prepared cake pans. Smooth top with small offset spatula. Bake cake layers in preheated oven to 33 minutes, or until center of cakes are firm and a toothpick inserted in the center of each cake comes out clean.
  • Remove cake pans from oven and cool on wire racks. Cool cakes completely before removing them from their pans and frosting. Remove parchment rounds from the bottom of cake layers. Level cake layers with a long serrated knife. Reserve the cut off portions, as we need them to coat the cake.

Chocolate Mousse:

  • Add finely chopped bittersweet chocolate to medium size metal or ceramic bowl. Set bowl over saucepan with 1/2-inch water. Heat the water over low heat. As the chocolate melts, stir with small spatula, until smooth. Set aside to cool.
  • Add egg whites to stand mixer. Using whip attachment, beat on medium high to soft peaks. Add granulated sugar to stand mixer, beat on low just long enough to incorporate. Transfer beaten egg whites to large mixing bowl. Set aside.
  • Add cold heavy whipping cream to stand mixer bowl. Using whip attachment, beat on medium high to soft peaks.
  • Add cooled melted chocolate to beaten egg whites in large mixing bowl. Gently fold together using large spatula.
  • Add heavy cream to chocolate mixture in large mixing bowl. Gently fold together using large spatula.
  • Chill until ready to use.

Black Cocoa Buttercream:

  • Add unsalted butter to stand mixer bowl. Using paddle attachment, beat the butter on medium speed until light and fluffy, about 5 minutes.
  • Add powdered sugar to stand mixer bowl. Beat on medium speed until light and fluffy, about 5 minutes.
  • Add the black cocoa powder and heavy cream to the stand mixer bowl. Beat on low until fully incorporated. Set aside.

Assembly:

  • Add the cake scraps to a food processor and process just long enough to turn into crumbs. Set aside.
  • Top two of the cake rounds with about 1/4-inch of chilled chocolate mousse, leaving about 1/2-inch of space at the edges. Place one of the mousse covered cake layers on top of the other. Place the remaining, unadorned, cake layer on top.
  • Lightly frost the sides of the cake with cocoa buttercream. Frost the top of the top of the cake with buttercream.
  • Take handfuls of the reserved cake crumbs and press them into the sides of the cake. Some will fall off, just be patient, and reapply.
Keyword black cocoa buttercream, black cocoa powder, chocolate mousse