Made these for my boyfriends birthday today, they are pretty damn yummy! However dont try and substitute icing sugar with granulated for the butter icing, just doesnt work in any way...
125g castor sugar
150g self raising flour
25g white chocolate (melted)
Spoon into cake cases and bake for 15 mins at 180 degrees. Cut the top off each cake, slice in half and then press into butter icing on top of the cake, i added chocolate buttons for fun :)
225g icing sugar