Chocolate Blackout Cake

Brooklyn blackout cake

  • serves 16
  • A little effort

Edd Kimber has put his own twist on this classic American chocolate cake by flavouring the custard filling with white chocolate and cardamom. The outside is decorated in a silky-smooth chocolate frosting to preserve the original cake's look and flavour.


 This Brooklyn blackout cake recipe is created by original GBBO winner and expert baker Edd Kimber.

Here’s Edd’s insider baking knowledge and inspiration for this recipe: The original version of this cake comes from post-war Brooklyn, created by the now long-gone Ebinger Baking Company. Originally it was layers of chocolate cake sandwiched and covered with a chocolate pudding (think thick Angel Delight or custard) and coated in cake crumbs

We’ve got plenty more indulgent chocolate cake recipes for you to try, such as this ultimate chocolate fudge cake.



  • unsalted butter 175g, soft
  • light brown muscovado sugar 300g
  • caster sugar 100g
  • vanilla extract 1 tsp
  • plain flour 275g
  • cocoa powder 50g
  • baking powder 1 tbsp
  • salt 1/4 tsp
  • strong coffee 150ml
  • whole milk 150ml
  • egg whites 5, lightly beaten


  • egg yolks 5
  • caster sugar 75g
  • cornflour 25g
  • whole milk 250ml
  • cardamom 1 tsp seeds, finely ground
  • white chocolate 75g, finely chopped


  • unsalted butter 100g
  • dark chocolate 150g
  • honey 1 tbsp
  • double cream 120ml


  • Step 1

    To make the custard filling, put the egg yolks, sugar and cornflour in a large bowl and whisk until light and creamy. In a medium pan, heat the milk and cardamom over a medium heat until just coming to a simmer. Remove from the heat and pour onto the egg yolks, whisking to combine. Pour the mixture back into the pan and whisk constantly until the custard has thickened and is smooth. Scrape back into the bowl and add the chocolate, stirring until fully melted and combined. Press a sheet of clingfilm onto the surface of the custard to prevent a skin from forming and chill for at least 2 hours.

  • Step 2

    To make the sponge, lightly butter and line 3 x 20cm round cake tins and heat the oven to 180C/fan 160C/gas 4. In a large bowl, cream the butter and sugars together until light and fluffy. Add the vanilla and beat to combine. Meanwhile, in a separate bowl, mix together the flour, cocoa powder, baking powder and salt. Pour the coffee and milk together into a jug. Add the egg whites to the butter mixture, a little at a time, beating until fully combined before adding more. Add the flour mixture to the cake batter in three additions, alternating with the coffee mixture. Divide the batter evenly between the prepared cake tins and bake for 30-40 minutes, or until the cakes spring back to the touch and are coming away from the sides of the tins. Allow to cool in the tins for 10 minutes before turning out onto a wire rack to cool completely.

  • Step 3

    To make the frosting, put the butter, chocolate and honey into a heatproof bowl set over a pan of simmering water and heat, stirring occasionally, until fully melted. Remove from the heat and pour in the cream, stirring together. Cool until the mixture has thickened to a spreadable consistency.

  • Step 4

    To assemble the cake, use a serrated knife to slice a thin layer of sponge from the top of each cake, creating flat, even layers. Put the offcuts into a bowl and crumble to make crumbs.

  • Step 5

    Put one cake onto a serving plate and top with half of the cardamom custard, repeat with the second cake and custard, then top with the remaining cake. To finish, spread the frosting over the top and sides of the cake and carefully press the cake crumbs over the whole cake. Kept in a sealed container this cake will keep for up to three days.

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Nutritional Information

  • Kcals 488
  • Fat 26.8g
  • Saturates 15.9g
  • Carbs 54g
  • Sugars 38g
  • Fibre 1.9g
  • Protein 6.5g
  • Salt 0.4g