The Family Kitchen is an awesome website chock full of unique baking recipes including this staggeringly beautiful Rainbow Cake in a Jar. The only ingredients you need for this show-stopping cake are:
1 box white cake mix made according to package instructions
Neon food coloring in pink, yellow, green, turquoise, and purple
3 one-pint canning jars
1 can vanilla frosting
For the full recipe, please click here. Other recipes on the site include Red Velvet and Nutella Cake in a Jar, and Birthday Cake in a Jar. After discovering this website, I may never use 9x13 pans again!