Prepare your pan by either spraying it with non stick spray, or lining it with aluminum foil or parchment paper. Be sure to still spray the aluminum foil or parchment paper. The foil/paper allow you to lift the batch easily out of the pan for easy clean up. Set prepared pan aside.
You will be dividing the cereal, marshmallows, and butter into three portions, one for each color. For each layer you will be placing 5 oz marshmallows and 2 tablespoon of butter into a large microwave safe bowl.
15 oz marshmallows, divided, 6 tablespoon butter, divided
For the red layer mix 5 oz marshmallow and 2 tablespoons butter into a large microwave safe bowl. Microwave 1 minute. Remove and mix well, then add the red gel colorant and mix in well. Return to the microwave for 15 additional seconds if needed, then add 2 ½ cups of the rice cereal mixture. Mix to coat the rice cereal and press layer into the prepared pan.
7 ½ cups Crisp Rice Cereal, divided, red gel food colorant
Repeat for the uncolored layer with 5 oz of the marshmallows, 2 tablespoons of the butter, and microwave in a large mixing bowl for 1 minute. Add the rice cereal and mix to coat with marshmallow mixture. Press into the pan on top of the red layer.
Repeat again for the blue layer by melting the last 5 oz of marshmallows with the last 2 oz of butter in a microwave safe mixing bowl. Mix well, add the blue gel food colorant, and mix well. Return to microwave for 15 seconds if needed, mix and add the rice cereal. Coat the cereal and press into pan on top of the uncolored mixture.
blue gel food colorant
Let cool for 30 minutes to 1 hour until cool and set up. Cut into 12 large bars or 24 smaller bars.