Place the butter in a large mixing bowl. Gradually add the icing sugar, alternating with the hot milk and beat with an electric mixer until the mixture is very pale and fluffy. Add the salt and vanilla and mix.
Variations:
Orange butter icing: Add 1 tbsp finely grated orange rind with the butter.
Coffee butter icing: Dissolve 2 tbsp instant coffee granules in the milk.
Chocolate butter icing: Reduce the icing sugar to 230g (1 1/2 cups). Omit the milk. Stir in 250g melted, cooled, NoMU Hot Chocolate Chunks.
Dark chocolate butter icing: Reduce the icing sugar to 300g (2 cups). Omit the milk. Sift in 2 tbps NoMU Cocoa Powder and then stir in 600g melted, cooled, NoMU Hot Chocolate Chunks.
