2 tsp strong coffee, dissolved in about 1tbsp of boiling water
Preheat oven to 180 Celsius. Then beat butter, sugar and cocoa together well.
In a separate bowl, beat yolk of eggs and mix with milk and vanilla. Then add this egg mixture to creamed butter and beat very well.
Gradually add sifted flour alternatively with water. Then fold in stiffly beaten egg whites and baking powder.
Pour mixture into two prepared (20cm) round cake tins and bake for half an hour.
To make icing, mix the icing sugar, butter and cocoa together and then add just enough of the coffee and milk/cream to get a smooth texture that is not too wet or runny.
When cake turned out on cooling racks and cool - ice the centre and then top and sides with the butter icing. You can crumble a flake chocolate over the top. Or if you're feeling adventurous - before you ice the cake cover it in a layer of caramel (the one that comes in the tin).