Preheat oven to 200°C/180°C fan & line a 12-hole muffin tin.
Mix 40g cocoa + 4 tbsp boiling water to form a thick paste.
Add eggs, butter, sugar, flour & baking powder & beat until smooth.
Divide into cases, bake 15 mins, then leave to cool.
Melt butter, mix with cocoa & icing sugar then add milk to loosen.
Pipe icing onto cupcakes, decorate and allow to set.
