This cake could also be called Brooklyn Chocolate Wonder. It’s definitely Brooklyn’s finest contribution to this world’s taste buds. I’ve been meaning to test it sometime now only because of it’s name. If you are a choc-o-holic like me, the word “blackout” doesn’t remind you, even remotely, of a massive power cut, but more of an intense, dark, chocolate heaven. And this is what this cake is all about.
For those of you who never heard of this amazing cake, let me try and describe it. Ideally I would like to describe it in Cypriot dialect so that I don’t run out of words, but you will hate me for it. So, I will recall all the English adjectives I know: It’s three layers of dense, moist, buttery, melt-in-your-mouth, fudgy, chocolate cake, sandwiched and frosted with the most heavenly, velvety, rich, creamy chocolate custard and finally coated in cake crumbs. How did I do?
Oh! I forgot divine.
Ingredients for the cake
- 1 cup plus 2 Tablespoons cocoa powder
- 1 Tbs instant coffee granules
- ¾ cup boiling water
- 1 cup sour cream
- ½ cup whole milk
- 1 tsp vanilla extract
- 125 grams unsalted butter, softened
- ½ cup sunflower oil
- 4 large eggs
- 1 ½ cup granulated sugar
- ½ cup soft dark brown sugar
- 2 ½ cups all-purpose flour
- 1 tsp baking powder
- 1 tsp baking soda
- ½ tsp salt
For the filling and frosting
- 1 ½ Tbs corn flour
- 1 ½ cup whole milk
- ½ cup cream
- ½ cup granulated sugar
- 2 Tbs cocoa powder
- 100 grams bittersweet chocolate (I used Cadbury’s Bournville), chopped
- 2 large eggs
- 1 tsp vanilla extract
- 4 Tbs unsalted butter
Note: It’s best to make the cakes and filling one day in advance. Splitting the cakes in half will be far easier once they chilled plus the custard will have time to cool, thicken and will be easier to spread.
Make the cakes: Preheat oven to 175 C. Line the base of 2 x 23 cm (9”) cake pans with greaseproof paper.
Put cocoa powder and coffee granules in a medium size heatproof bowl. Pour over the boiling water and whisk to dissolve. Add the sour cream, cold milk and vanilla. Whisk again to combine.
In a bowl of a stand mixer, add the softened butter and oil. Mix until almost combined. The mixture will not look totally mixed and that is ok. Add the eggs one at a time and mix until combined. Add the cocoa mixture and whisk again.
In another bowl add the sugars. In the same bowl sift the flour together with the baking powder, baking soda and salt. Mix everything together with a spatula.
Add the flour mixture to the mixer bowl. Whisk until you have a smooth cake batter.
Divide the batter equally in the prepared cake pans. Bake in the preheated oven for 30-35 minutes until a cake tester in the centre of each cake comes out clean.
Run a small metal spatula around the edges of each cake to release it. Invert cakes on plates and remove greaseproof paper from the base. Re-invert cakes on a wire rack so that they are the right side up. Cool completely to room temperature. Then wrap tightly in plastic wrap and refrigerate for up to 24 hours.
Make the filling and frosting: Put the corn flour in a small bowl. Add about 2 Tbs of the milk and stir to dissolve. Set aside.
Put the remaining milk in a saucepan together with the cream and sugar. Turn the heat to medium and as soon as mixture starts to heat a little whisk in the cocoa powder. Just as soon as the milk mixture starts to steam a lot (not boil), remove from the heat. Add the chopped chocolate and stir with a spatula until chocolate melts and mixture is smooth.
In a bowl of a stand mixer fitted with the whisk attachment add the eggs, corn flour mixture and vanilla extract. Beat to combine.
Reduce the speed to medium-low and slowly pour in the warm milk-chocolate mixture while beating constantly. Transfer mixture back to the saucepan and place over medium-low heat. Stir constantly (I like to use a whisk to dissolve any lumps) until cream is thickened and starting to boil.
Remove from heat and whisk in the butter. Whisk until butter has melted and cream is glossy and smooth. Transfer cream into a heatproof bowl. Cover the surface with plastic wrap (the plastic must touch the surface of the cream). This will keep the cream from forming a skin while it cools. Cool to room temperature for about 2 hours, and then transfer to the fridge. Cream can be prepared and kept in the fridge 48 hours in advance.
Assemble the cake: Split the two cakes in half. Set aside the least attractive layer. You will be using that later for making cake crumbs.
Whisk the chocolate custard to loosen it. Place one cake layer on a cake platter. Spread with a little less than 1 cup of the custard. Repeat with another cake layer and custard. Finish with a third cake layer and cover the entire cake with the remaining chocolate custard.
Use your hands to turn the last layer into crumbs. Don’t crumb the whole layer as you may not need all of it and it would be such a shame to waste. I use about half of it and eat the rest with a cup of coffee.
Sprinkle the top and sides of the cake with the crumbs. Return cake to the fridge for at least 2 hours before serving. Serve chilled.