Really simple chocolate sponge cake

For the cake: Preheat the oven to 180 C / Gas 4. Grease two 23cm cake tins.

Cream together the caster sugar and the 340g butter. Add the eggs. Mix together.

Add the self raising flour. Mix together. Add the cocoa powder. Mix together. Divide the cake mixture evenly between the two tins.

Bake in the preheated oven on the middle shelf until a skewer inserted near the centre comes out clean, about 30 minutes. Allow the layers to cool for 30 minutes.

Meanwhile, make the buttercream: Beat the 220g butter until soft. Add half of the icing sugar and beat until smooth.

Add the remaining icing sugar, the cocoa powder and 1 tablespoon milk. Beat until creamy (add more milk to loosen if necessary).

Use half of the buttercream for the middle filling and half for the top. Decorate with chocolate buttons.