How do you make coffee cake?

Coffee cake topping without butter For the filling and topping: 1 level tablespoon instant espresso coffee powder
1 rounded tablespoon golden caster sugar
10 walnut halves, reserved from the sponge cake
9 oz (250 g) mascarpone
7 fl oz (200 ml) 8 per cent fat fromage frais Ingredients
For the cake
225g/8oz unsalted butter, plus extra for greasing
225g/8oz caster sugar
4 free-range eggs
50ml/1¾fl oz strong espresso coffee
225g/8oz self-raising flour
1 tsp baking powder
75g/2½oz walnuts Method
1. Preheat the oven to 180C/350F/Gas 4.
2. In a bowl, beat the butter and sugar together until very light and pale.
3. Add the eggs one at a time to the butter and sugar mixture, beating well to completely incorporate each egg before adding the next egg.
4. Add the espresso to the mixture and stir well.
5. Add the flour, baking powder and walnuts and stir well to completely combine.
6. Spoon the cake mixture into two lined and greased 20cm/8in cake tins.
7. Transfer to the oven to bake 25-30 minutes, or until a skewer inserted into the centre of the cake comes out clean and the cake is golden-brown.
8. Remove the cakes from the oven and leave to cool on a wire rack. Spread the butter cream over the top of each cake, then place one cake on top of the other. Decorate the top of the cake with the walnut halves and serve in generous slices.