This is simply adorable. Great April Showers Celebration with a Rainbow Cake. Great for Easter and Springtime fun. How about a Rainbow Birthday party. It is endless how you could celebrate. I was so excited when I found it...
Preheat oven to 350F. Thoroughly wash and dry the inside of canning jars. Spray the inside of each jar thoroughly with non stick cooking spray. Set aside.
Prepare cake as directed on pkg. Scoop about 1/2 cups of batter into five small bowls. It doesn't have to be perfect. Tint each bowl of cake batter with the food coloring until very vibrant.
Pour about 3 tbsp of the purple batter into the bottom of each jar. Spoon equal amts of the rest of the colors. Place jars in a shallow baking dish, add about 1/4" of water in the baking dish. Place the baking dish in the oven and bake 30-35 min.
Remove jars and allow to cool completely before scooping a small portion from the top of the cake. Add a good dollop of frosting. Sprinkle with rainbow sprinkles.