- icing sugar
- food paste colouring, 2 types
To make the icing, put the butter into the mixing bowl of an electric mixer and blend on high speed until mixed. It's best to use butter at room temperature.
Pour in half of the icing sugar and blend until fully incorporated. Add the other half of the icing sugar and blend. Increase the mixing speed as the sugar and butter incorporate. Add milk and blend.
Put the buttercream icing into two separate bowls and, using a wooden skewer, add one food colouring to each until the icing is completely coloured. Don't worry if the colour is streaky.
Take a piping bag with a star nozzle, invert the bag over your hand and spoon in the first colour. Taking a skewer, make a cavity in that icing and spoon the second colour of icing into the cavity.
Push the buttercream down and pipe the icing on a cupcake to create a multicoloured swirl.