Beat the butter and sugar together until light and fluffy. Gradually beat in the eggs, milk and peppermint essence. If mixture starts to curdle, add a little of the flour.
Sieve the cocoa and flour and fold into the butter and sugar mixture.
Place spoonfuls of the mixture into the baking cases and bake for 20 minutes until golden and firm to the touch.
Cool on a wire tray and decorate with mint butter icing.
For the mint butter icing beat all ingredients until light and airy. Pipe on your cupcakes and top with a chocolate button or flake