75g/3oz/6 tbsp unsalted butter, softened
175g/6oz/1 cup icing (confectioner’s) sugar, sifted
a few drops of vanilla extract
1–2 tbsp milk
1 Put the butter in a bowl and beat with a wooden spoon until light and fluffy.
2 Gradually stir in the sugar, vanilla extract and milk. Beat until light and smooth.
3 This is enough to cover the top of a 20cm/8in cake.