Brooklyn Blackout Cake

For Mother’s Day this year my mother had one request – Brooklyn Blackout Cake. She had not had it in what felt like forever and I decided I was up to the challenge – and a challenge it was! From start to finish this cake took nearly five hours to complete. If you’re going to make this, devote an afternoon to it. With that said, below is my take on this cake (I combined three different recipes to make this happen).

• Cake Ingredients:
• 1/2 cup Dutch-processed cocoa powder
• 2 tablespoons boiling water
• 2 ounces unsweetened chocolate, chopped
• 3/4 cup whole milk
• 1 cup (2 sticks) unsalted butter, softened
• 2 cups sugar
• 4 eggs, separated
• 2 teaspoons vanilla extract
• 2 cups AP flour
• 1 teaspoon baking powder
• 1 teaspoon baking soda
• 1 teaspoon salt

• Filling Ingredients:
• 1 tablespoon + 1 3/4 teaspoons Dutch-processed cocoa powder
• 2 cups boiling water
• 3/4 cup + 1 tablespoon + 1/2 teaspoon sugar
• 1 ounce bittersweet chocolate, chopped
• 3-4 tablespoons corn starch dissolved in 2 tablespoons very cold water
• 1/4 teaspoon salt
• 1 teaspoon vanilla extract
• 2 tablespoons unsalted butter

• Frosting Ingredients:
• 12 ounces semisweet chocolate, chopped
• 12 tablespoons (1.5 sticks) unsalted butter
• 1/2 cup sugar
• 1/2 cup hot water (not boiling)
• 1 tablespoon light corn syrup
• 1 tablespoon vanilla extract

1. Make the cake: place cocoa powder in a small bowl and whisk in the boiling water until it forms a paste.
2. Combine unsweetened chocolate and milk in a small saucepan over medium heat, stir until the chocolate completely melts and remove from heat. Whisk a small amount of the hot chocolate milk into the cocoa paste to warm it. Whisk the cocoa mixture into the milk mixture. Return the saucepan to medium heat and stir for one minute, remove and set aside to cool slightly.
3. Preheat oven to 375 degrees F.
4. Butter and flour two 8-inch round cake pans.
5. In a mixer, cream the butter and sugar. Beat in egg yolks (one at a time). Add vanilla. Remove from mixer and stir in chocolate mixture.
6. Combine flour, baking powder, baking soda, and salt. Slowly add flour mixture to the chocolate mixture, folding in until just combined.
7. In another bowl, beat the egg whites until soft peaks form. Gently fold the egg whites into the batter. Divide the batter between the two prepared pans. Bake until a toothpick in the center of both cakes comes out clean, about 45 minutes.
8. Cool the cakes in their pans, on a cooling rack for 15 minutes. Remove cakes from pans and continue to cool.
9. Make the filling while the cakes are baking: combine the cocoa powder and boiling water in a small saucepan over low heat. Stir in sugar and chocolate. Add dissolved corn starch paste and salt to the saucepan and bring to a boil, stirring constantly. Boil for 1 minute. Remove saucepan from heat, whisk in vanilla and butter, transfer mixture to a bowl. Cover and refrigerate until cool.
10. Make the frosting: melt the chocolate in a double boiler, stirring until smooth. Remove the top of the double boiler and whisk in butter (1 tablespoon at a time). Return to heat if necessary to melt the butter completely.
11. Whisk in hot water, all at once, until smooth. Whisk in corn syrup and vanilla. Whisk in sugar until all combined.
12. Cover and refrigerate for 15 minutes. Remove from refrigerator, stir, re-cover, and let it sit on counter for about 15 minutes until it forms a smooth working consistency.
13. Assemble the cake: using a sharp serrated knife slice each cake horizontally in half to form 4 layers. Set 1 layer aside for crumbling.
14. Place one layer on a cake round or plate. Generously coat top of layer with filling. Add second cake layer, repeat with filling on top. Add third layer, put a very thin coat of filling on top. Refrigerate for 10 minutes.
15. Remove from refrigerator. Frost top and sides of cake with frosting. Crumble remaining layer and using your hands liberally apply crumbs to side and top of cake. Store in a cool place.

This came out delicious (and beautiful). I would definitely make this again but it did wipe out my energy for the day!