Line a deep straight- edged 9 x 13 pan with foil extend over two sides. Coat with cooking spray.
Melt 3 Tbsp. Butter in a large sausepan over medium low heat. Add one package regular marshmallows. Stirring until melted and smooth.Remove from heat stir in 6 cups rice krispies. Using a rubber spatula coated with cooking spray. Press firmly into pan . Set aside.
In a clean sausepan. Melt 3 Tbsp. Butter. Add remaing pack of regular marshmallows stir until melted. Stir in cocoa krispies until evenly coated. Press firmly over plain layer. Set aside.
Melt remaining 3 Tbsp. Butter in a clean sausepan. Add strawberry marshmallows stirring until coated. Press firmly over cocoa layer. Refrigerate until chilled.
Invert pan onto cutting board to remove cereal . Remove foil and cut.
