Because I had never made one, and they were becoming more and more popular on the internet I thought I would have a go. Turns out it's pretty easy with a store bought cake mix and some food colouring.
Prepare the cake as per instructions. Separate batter into bowls. Add colouring to each. Pour each into cake tin, don't mix. Bake. Ice. Honestly, I'm not a fan of cake. I think I turned 14 when I started telling my mother not to bother with birthday cakes. They're okay, but not really my thing. I really just did it for novelty.