Black Cocoa Cake

Seeing as Halloween is upon us, let’s go dark… but with chocolate! Let’s face it, what colour is most synonymous with all things spooky & Halloween? Black of course! That’s why this year I wanted to make an entirely black, spooky themed cake but without heavily relying on food colouring. I’ve been enjoying baking a lot with black cocoa this year, for it’s less sweet flavour & dramatic colour, which works brilliantly in brownies & cakes. Dark cocoa has much more bitterness than regular cocoa powder, which is exactly what we want when you’re putting this much sugar into a cake!

Here I’ve used it to create 3 layers of rich, earthy, black chocolate cake smothered & filled with a black chocolate buttercream. This has a wonderfully moist, tender crumb which isn’t overly sweet but is balanced out with that dark buttercream. This black cocoa cake is not just good for Halloween, but it works pretty damn well when you add on some on theme decorations!

(makes an 18cm layer cake)


For the cake:

  • 225g plain flour
  • 400g caster sugar
  • 100g black cocoa powder
  • 1 tsp baking powder
  • 1 1/2 tsp bicarbonate of soda
  • Pinch of salt
  • 2 large eggs
  • 225ml buttermilk
  • 110ml rapeseed oil
  • 1 tsp vanilla extract
  • 80ml boiling water

For the black cocoa buttercream filling & covering:

  • 450g butter
  • 400g icing sugar
  • 220g black cocoa
  • 2 tbsp milk

Optional – For the decoration:

  • Dark 70% chocolate, melted


To make the cake:

  • In a large bowl sift together the flour, sugar, cocoa, raising agents & salt
  • In a separate bowl or jug, whisk together the eggs, buttermilk, oil & vanilla
  • Next, make a well in the centre of the dry ingredients, pour in the buttermilk mixture & beat everything together until just combined
  • Finally, add the boiling water to the bowl & beat until smooth & no pockets of dry flour remain
  • Divide the mixture evenly between 3 greased & lined 18cm sandwich tins
  • Bake in the oven at 180C for 30-35 minutes, until risen & the cakes are springing back to the touch when pressed lightly with a finger in the centre
  • Leave the cakes to cool in their tins for 10 mins before removing & placing on a wire cooling rack until cooled

To make the black cocoa buttercream:

  • In a large bowl, beat the butter to soften it a little
  • Add half of the icing sugar to the bowl & beat until combined
  • Add the rest of the icing sugar to the bowl & beat again until smooth
  • Beat in all of the cocoa to the buttercream until fully incorporated
  • Add in enough milk until have a nice smooth buttercream

To assemble the cake:

  • Secure the bottom sponge layer of the cake to it’s plate or stand with a little of the buttercream
  • Use a spatula to generously spread 1/3 of the buttercream on top of the cake layer
  • Repeat the process using the remaining 2 cakes & sandwich all 3 of the together, pressing each cake layer down a little when added
  • Use the remaining buttercream to cover the sides & top of the cake before using a large palette knife to smooth off the surface
  • Decorate with a drizzling of melted dark chocolate or decorations as desired

Leave a Reply