I'm only calling it carnival cake because for my little girl's 3rd birthday I want to make the inside of her carnival themed cake (a carousel) look bright and festive. So I thought I would try out my theory early because I was curious! It worked.
So I started by using a normal cake mix...yellow. Next time I might try white just to see if the colors are brighter. I seperated the batter into seperate mixing bowls and added the gel coloring.
Then I striped the colors into the pan...it was thick enough it didn't run very much. I wasn't looking for perfect stripes anyway...just a bunch of unmixed color!