Creaming Butter and Sugar

I have usually suggested 5 minutes to cream the butter and sugar - both for a cake and for buttercream - and, should you time yourself, you will see it is quite a while. The reason is that there is a very noticeable difference: the colour changes and the mixture becomes aerated as it increases in volume, turning paler and fluffy. Keep scraping the sides of your bowl with a spatula during the process to make sure all ingredients are well blended in.