The Great British Bakeoff

In the spirit of the bake off i made some chocolate coffee cupcakes. The cake bake part is fine but for some reason i have issues with my buttercream! Surely that should be the easy bit! Upon discussion at school with some other keen bakers it could be the kitchen is too warm when i make them and so the butter cream splits. Sound plausible. Will have to try again, but even so they still look and taste yummy!