- 250g pack softened butter, plus extra for the tins
- 100ml strong black coffee (made with 2 tbsp coffee granules), cooled
- 280g self-raising flour
- 250g golden caster sugar
- ½ tsp baking powder
- 4 eggs
- 1 tsp vanilla extract
- 85g walnuts, 2 tbsp roughly chopped, the rest finely chopped
For the filling
- 100g icing sugar, sifted, plus a little extra for dusting
- 150ml double cream
- 100g mascarpone, at room temperature
- Heat oven to 180C/160C fan/gas 4. Butter 2 x 20cm round cake tins and line with baking parchment. Set aside 1 tbsp of the coffee for the filling.
- Beat the butter, flour, sugar, baking powder, eggs, vanilla and half the remaining coffee in a large bowl with an electric whisk until lump-free. Fold in the finely chopped walnuts, then divide between the tins and roughly spread. Scatter the roughly chopped walnuts over one of the cakes. Bake the cakes for 25-30 mins until golden and risen, and a skewer poked in comes out clean. Drizzle the plain cake with the remaining coffee. Cool the cakes in the tins.
- Meanwhile, make the filling: beat together the icing sugar, cream and mascarpone, then fold in the reserved 2 tbsp coffee. Spread over the plain cake, then cover with the walnut-topped cake and dust with a little icing sugar.