- 600g icing sugar, sifted
- 300g unsalted or salted butter, softened
- finely grated lemon zest
- finely grated orange zest
- a dash of vanilla extract
- few drops food colouring
- cocoa powder, to taste
Beat the icing sugar and butter together, with your chosen flavouring and colouring if using, until smooth. Choose unsalted butter for a celebration cake. Salted is good for cupcakes. Fill a piping bag with a star nozzle and pipe onto cupcakes or smear in the middle and over the top of a 20cm cake using a palette knife.
Quantities for buttercream
A ratio of equal quantities of icing sugar and butter works well unless you’re adding a significant quantity of a liquid eg juice of an orange or lemon or melted chocolate. If you are, you can increase the quantities of icing sugar. You might want to add as much as double. Add gradually if you like, and make sure it is sifted, to get the consistency you want.
Keeping the icing
If you’re not using the icing straightaway, you can cover it and refrigerate for up to a week. Allow it to come back up to room temperature and beat again if necessary before using.
Celebration cake ratios
10cm (4 inch) cake: 150g buttercream 13cm (5 inch) cake: 225g buttercream 15cm (6 inch) cake: 300g buttercream 18cm (7 inch) cake: 450g buttercream 20cm (8 inch) cake: 600g buttercream 23cm (9 inch) cake: 750g buttercream 25cm ((10 inch) cake: 900g buttercream 28cm (11 inch) cake: 1.2kg buttercream 30cm (12 inch) cake: 1.5kg buttercream