I picked this little skill up from a cousin of mine and I LOVE it. How cute and creative are tie dye cupcakes/cakes? You can easily personalize the colors for a party's theme, bridal colors, etc.
I separated my prepared (and rather white) cake batter, then dyed it with food coloring. I made this batch for a Valentine activity, but I have also done rainbow ones. You could pick whatever colors you like.
Just spoon the batter into your pan/cupcake wrappers. It doesn't need to look pretty.
Once baked, they look like this! I also took it to the next level and dyed my frosting. Again, I just filled my piping bag spoonful by spoonful with the different icing colors. As a tip--refrigerate your icing BEFORE filling your piping bag as well as AFTER so the colors don't blend themselves together too quickly.