No time to bake a multi-layered rainbow cake. Try this easy alternative. Prepare cake batter as per pack instructions then separate into equal parts. Colour each part with food colouring - creating as many colours as you like. Pour coloured batter randomly into the cake tin. DONT MIX THEM. Just let them fall randomly. Bake the cake as per pack instructions. This cake was done using two Green’s Vanilla Sponge Cake mix packets and covered with Betty Crockers Vanilla icing. EASY AS!