I used dark chocolate and a little cocoa for a chocolate boost and some strong espresso coffee.
Preheat oven 180C/gas4 Grease and base line a 900g loaf tin.
In a bowl mix together 200g plain flour, 2 tspn baking powder, 1 tbspn cocoa, pinch of salt and 200g caster sugar.
Melt 125g dark chocolate over simmering water or in the microwave then add 125g of chopped up butter and 150ml of espresso coffee and mix together till smooth.
Separate 3 eggs and add the yolks one at a time to the mixture. Add the flour mixture and mix together. Whisk the egg whites till stiff then gently fold these into the batter. Pour into the tin and bake for 45-50 mins.
Cool in the tin for 10 mins, then finish on a wire rack.
For the icing - 50ml strong coffee, 300g sieved icing sugar and 50g soft butter.
Beat the 3 ingredients together to make a paste then smooth over the cooled cake. Chill for about 2 hours before serving to allow the icing to set.
I roughed my icing up a bit with a fork as it didn't look too smooth! The cake had a great mocha flavour - maybe more coffee than chocolate, but delicious. It had a good texture and the cake contrasted well with the smooth coffee icing.