1. Preheat the oven to 180°c.
2.  In a large bowl cream together  the butter and caster sugar with the electric whisk until pale and fluffy.
3. One by one, slowly beat in the eggs.
4. Now add the walnuts, espresso powder, plain flour and baking powder. Mix in nicely with a wooden spoon and then add the milk.
5. Divide the mixture and pour into two greased 20cm sandwich tins. Bake for 30mins.
6. While baking, make the frosting by beating the butter and coffee in a bowl. Sieve in the icing sugar and beat. Set aside until needed.
7. Once the cake is cooked, allow it to cool for 20mins in the tin before transferring to a wire rack. Once cooled you assemble your cake. Place half the frosting in the middle of the cake spread well out to the edges. Then layer the top half on and spread on the rest of the frosting.

Finish with a nice sprinkle of the walnuts and then enjoy!