This is a very versatile and easy icing which can be used as a filling, a coating and for simple piping. The only ingredients are softened unsalted butter and sifted icing sugar, with added flavourings (such as vanilla, almond, peppermint, lemon juice and rind, or flower water) and colourings. You can also mix the ingredients together in a food processor.
Makes enough to fill and cover one 20-23cm (8-9in) round cake or top 18-24 small cakes.
Beat 125g (4oz) softened unsalted butter until light and fluffy. Sift 250g (8oz) icing sugar gradually on top, beating well with a wooden spoon. Scrape the sides of the bowl down with a rubber spatula.
Beat in a few drops of flavouring. Add colouring if desired, a drop at a time, from the tip of a cocktail stick. If the buttercream is too stiff, stir in 1tablespoon milk, water or fruit juice to help lighten it.
Spread the buttercream with a palette knife first round the sides of the cake, then on top. Run the tip of the knife back and forth over the top for a simple but effective pattern. Or bring the icing up over the cake in little flicks.