i baked rainbow cupcakes for my D&D group and my friend on furc, tinkleh.

i loves to bake rainbow cake. it's really easy to do, too! if you want to know how, lemme know in the comments and i can edit this to have the SECRET OF RAINBOW CUPCAKES

//edit

THE SECRET OF RAINBOW CUPCAKES IS BELOW THIS LINE

first you need
-regular cake making supplies
-white cake mix
-food colouring (gel colours work best)
-several small bowls (cereal bowls)
-a regular mixing bowl

mix your batter like normal in the big bowl. then distribute it into the smaller bowls so you have several small bowls all with batter in them.

put the dye into the small bowls, mixing whatever colours you want. gel colours bake brighter than other colours, so if you want really bold looking cupcakes or cake, stick with gel colours.

use a spoon to put colours into the cupcake papers in your cupcake tin. do this one colour on top of the other. don't try to mix them in the paper or "flatten" the batter. it'll naturally get a cool ripple/layer effect in the oven if you just leave it be.

the same goes for making a cake, just pour the bowls in one colour directly on top of the other.

aaaaand bake like normal! tada! rainbow cupcakes/cake!