For the cake:
- 130g plain flour
- 1 tsp baking powder
- 1/2 tsp bicarbonate of soda
- 1/8 tsp salt
- 100g peanut butter (I used crunchy)
- 45g unsalted butter, soft
- 50g caster sugar
- 50g soft brown sugar
- 75g (1.5) eggs, lightly beaten
- 75ml buttermilk
For the chocolate ganache:
- 150g dark chocolate (approx 72%)
- 125ml double cream
- 25ml buttermilk
- 1 tbsp light brown sugar
- small handful of peanuts (I used salted)
- approx 1 tbsp cocoa nibs
- Preheat the oven to 180C. Butter and flour a 6″ cake tin (double all ingredients for a 9″ tin or two 8″). Sieve the flour, baking powder, bicarbonate of soda and salt into a bowl.
- Weigh the peanut butter, butter, caster sugar and brown sugar into the bowl of a stand mixer. Cream together, beating for about 4 minutes until light and fluffy. Scrape down the bowl with a spatula. Add the egg in small splashes, beating very well in between. When the egg is incorporated, clean down the sides then add half the flour. Mix on low speed until the mixture starts looking uniform, then add the buttermilk in a steady stream. Once you’ve added all the buttermilk, take the mixture off the stand mixer. Add the rest of the dry ingredients and fold in with a spatula.
- Transfer to the prepared tin and level. Bake for 30-35 minutes or until a toothpick can be removed cleanly from the middle. Leave in the tin for five minutes then transfer to a wire rack to cool. When the cake is totally cool, split it into two or three layers with a serrated knife.
- To make the ganache, chop the chocolate up into small chunks and place it into a bowl. Put the double cream, buttermilk and brown sugar in a small pan and warm over a medium heat. When it starts to steam, pour over the chocolate, pushing all of the chunks into the liquid. After a few moments start stirring in the centre, slowly incorporating the rest of the liquid until you have a thick, glossy ganache. Leave to cool for a few minutes to thicken slightly.
- Place the layer that was the top of the cake upside down on the serving plate on top of some strips of parchment paper. Smear some ganache over the layer, then add the next cake layer. Repeat for the next layer if you cut into three. Cover the cake with a thin layer of icing – a masking coat – then put in the fridge to chill. Finally cover the cake with a full layer of ganache, trying not to overwork it. Arrange the peanuts and cocoa nibs on top of the cake for contrasting crunch.
- Best served at room temperature, though it keeps well covered in the fridge for a few days.
(Makes approximately 8 slices)