Preheat the (fan) oven to 170°/ 325°F/ GM3
Grease and line 3 x 6-inch circular baking tins (note these are smaller than average tins - if you are using 8-inch tins see my notes on how to scale up the recipe)
In a bowl beat the butter and sugar until light and fluffy, using electric beaters.
Crack the eggs into a small jug and beat. Add to the creamed butter and sugar, a little at a time, beating well between each addition (this helps reduce the risk of the batter splitting)
Stir the flour and baking powder together in a bowl and sieve over the cake batter. Mix in
Divide the cake batter equally into 3 small mixing bowls (digital scales help here)
To the first bowl stir in 1½ tsp of the cooled coffee and the vanilla extract
To the next bowl add the cocoa powder (sieved) and 2 tsp of the cooled coffee. Stir until just mixed in
To the final bowl add 1 tablespoon cooled coffee and mix in
Store the leftover coffee for the buttercream
Pour the cake batters into the prepared tins and bake for 20-23 minutes until the cake springs back when lightly pressed or a skewer comes out clean
Let cool in the tins for 2 minutes, then remove from the tins, peel off the baking parchment from the bottom of each sponge cake and let cool completely on a wire rack