What you need is:
Boxed white cake mix
3 egg whites
1/3 cup vegetable oil
1 1/4 cup water
Neon and regular food coloring
Non-stick cooking spray
Make cake batter according to the directions on the cake mix box.
Divide batter evenly between 6 bowls and add food coloring to make your rainbow colors!
Preheat over 350 degrees.
Spray the inside of your glass jars to the top with a generous amount of non-stick cooking spray.
Layer each color by pouring your batter slowly into the jar.
Each jar should only have about 1 cup of batter.
Place your jars in a baking dish with an inch of water at the bottom of the dish surrounding the jars.
Bake for 35-40 minutes.
Be sure to keep an eye on your jars and use the knife test!
Allow cakes to cool completely before frosting!
Pretty please! With a cheery on top!
Let your freak flag fly!