140g/5oz butter, softened
280g/10oz icing sugar
1-2 tbsp milk
few drops food colouring (optional)
Beat the butter in a large bowl until soft. Add half of the icing sugar and beat until smooth.
Add the remaining icing sugar and one tablespoon of the milk and beat the mixture until creamy and smooth. Beat in the milk, if necessary, to loosen the mixture.
Stir in the food colouring until well combined.