Royal icing

1. Beat the egg whites well and add the sifted icing sugar a spoonful at a time, beating well after each addition. (The final texture will depend on this process being correctly carried out.) It is best to beat the mixture with a wooden spoon so that no air is incorporated. If you’re using an electric mixer, work on a slow speed.
2. The texture is correct if the icing forms a peak when a knife is drawn through the mixture. Add the flavouring and tartaric acid. Carefully add colouring, if desired (a few drops of blue colouring will whiten the icing).
3. Cover the icing with a damp cloth or cling film. Before using the icing, remove air bubbles with a knife.