Blondies:
1 box yellow (or Funfetti!) cake mix
1/4 cup vegetable oil
1 egg
1/3 – 1/2 cup milk
1/4 cup rainbow sprinkles (if you use a yellow cake mix, add these in)
1/2 cup white chocolate chips
Sprinkles for the top
Frosting:
1/2 cube margarine or butter, softened
2-3 Tbsp milk
1 tsp vanilla
2 cups powdered sugar (more or less depending on how thick/runny you like it)
Recipe
Blondies:
Combine the cake mix, oil, and egg in a large bowl. Add the milk slowly – you want the batter to remain as dense as possible. Then mix in the rainbow sprinkles and white chocolate chips. Put batter in a 8x11" pan (or 9x9" pan would work too!). Bake for 25-30 minutes at 350 degrees. (They will be a little soft/gooey in the middle- just let them sit for about 20-30 minutes and they will set up. But I guarantee that you will not be able to wait that long.) Frost when cooled (optional . . . these taste amazing without frosting, but I am a serious frosting lover, so I added just a little bit).
Frosting:
Combine all ingredients until well-blended. Spread on top of blondies.