This is probably my most requested frosting/icing/addictive substance that goes on cakes. It works beautifully on cupcakes and large cakes and is a favourite with both children and adults!

Ingredients
Note: This makes HEAPS and I often halve or only use 3/4 of the recipe, however if you want really thick icing or will make a second batch soon after, the full recipe is the way to go (it lasts for about a week)
200g butter, softened
½ cup milk
1 tblspn vanilla extract
8 cups icing sugar
A few drops of food colouring/flavouring as desired

Method
Cream the butter for 1-2 mins in a large bowl using an electric mixer. Add the milk, vanilla and half of the icing sugar and beat for at least 3 mins (until the mixture is light and fluffy). Add the remaining icing sugar and beat for a further 3 mins or until of a spreadable consistency. Add extra milk if too dry or extra icing sugar if too wet. Add  colouring/flavouring and beat in until combined and the desired colour/flavour has been achieved.

Using a knife or piping bag, apply buttercream to cupcakes or cake and decorate as desired.

Adapted from the Crabapple Cupcake Bakery Cookbook