Melt butter in a large saucepan over low heat and add marshmallows. Stir until they begin to melt, adding in cake mix one spoonful at a time so its combined.
Stir in cereal so it is completely coated with marshmallow mixture.
Pour in half of the sprinkles and mix.
Press into a baking dish (I used a 9x13) and top with remaining sprinkles.
Let sit for about 30 minutes before cutting. Using a knife coated with nonstick spray makes cutting them much easier.
Recipe by Coupon Cutting Mom at https://couponcuttingmom.com/frugal-family-fun-cake-batter-rice-krispies-day-3/