MAKES 1 x 20cm · 8in CAKE
225g · 8oz unsalted butter softened plus
extra for tin
225g · 8oz golden caster sugar
4 medium eggs
225g · 8oz self-raising flour
2 tsp baking powder
100ml · 3½ fl oz cold espresso
FILLING
100g · 3½ oz unsalted butter softened
100g · 3½ oz icing sugar sifted
1 tbsp cold espresso
ICING
150g · 5oz icing sugar sifted
2 tbsp cold espresso
30g · 1¼ oz unsalted butter softened
TO FINISH
chunks or shavings of fudge or walnut halves
icing sugar for dusting
♥ Preheat the oven to 190C/170C fan/gas 5. Butter two 20cm · 8in loose-bottomed cake tins at least 4cm · 1½ in deep and line the bases with baking paper.
♥ Using an electric whisk on high speed, first whisk the butter in a large bowl for 1-2 minutes until very pale and fluffy, then add the sugar and continue to whisk for another 1-2 minutes. Add the eggs one at a time, whisking well with each addition until the mixture is amalgamated. Sift and whisk in the flour and baking powder in two goes, just lightly, then whisk in the coffee. Divide the mixture between the tins, weighing them for accuracy, and bake for 30-35 minutes until a skewer inserted in the centre comes out clean. Run a knife around the edge and leave to cool.
♥ For the filling, cream the butter in a medium bowl using an electric whisk for about 1 minute until very pale and fluffy, then gradually whisk in the icing sugar and whisk for 1 minute longer. Finally whisk in the coffee. Remove the collars from the cake tins and peel off the base papers. Spread one sponge with the filling, taking it up to the edge (for a professional finish, you can pipe a decorative rim, as in the picture). Place the second sponge on top.
♥ For the icing, blend the icing sugar and coffee together to a smooth paste in a medium bowl, then gradually whisk in the butter in small pieces using an electric whisk at high speed, to create a thick but light frosting. Slather this over the top of the cake using a palette knife and taking it up to the edge.
♥ Decorate with chunks or shavings of fudge (or walnut halves, if you prefer), dust with icing sugar and set aside in a cool place for a couple of hours for the buttercream filling to set and the icing to harden slightly. Loosely cover and store in a cool place. The cake will keep well for a couple of days.