Spray a 9×13 pan with nonstick cooking spray and set aside.
Place each color of peeps in their own large mixing bowl. Place the mini marshmallows in their own mixing bowl as well.
Add 3 tablespoons of butter to each of the four bowls.
Add the purple bowl to the microwave and heat on high for 1 minute and 15 seconds.
Stir well until no color streaks appear. If you want a brighter or more prominent purple, add a couple drops of the food dye here.
Immediately pour 4 cups rice cereal into the bowl and mix until the marshmallow is evenly distributed.
Quickly pour into the prepared pan. Spread the mixture until it’s evenly across the bottom of the pan and press down to pack it in.
Repeat steps 4-7 with the pink, white, and blue, in that order.
Cover the pan and let it rest for 3 hours or until the treats have dried enough to be cut and not be overly gooey.
