It’s important that all the ingredients are at room temperature when working them together. If the butter or eggs are too cold it can result in a curdled mixture. Add the eggs slowly, beating well after each addition, to allow the mixture to aerate rather than becoming a liquid sloppy state. Mix, mix, mix is the key to avoiding the dreaded curdle! Adding something very acidic to a cake mix such as lemon juice will cause a curdle. At the end of the day don’t worry too much – it’s best avoided if you can but if not your cake will still turn out pretty well!