Prepare your pan by lining it with parchment paper to prevent sticking.
In a large saucepan, melt the butter over medium heat, stirring occasionally. Once melted, add the marshmallows and continue stirring until completely melted and the mixture is smooth, about 3-5 minutes. You should hear a gentle simmer and see the marshmallow mixture turn shiny.
Remove the saucepan from heat. Quickly add the rice cereal to the marshmallow mixture and fold gently with a spatula until evenly coated. The mixture should be sticky and well combined.
Divide the mixture into three portions. Color one portion red, another blue, and leave the third white, mixing in food coloring or candies to achieve vibrant red and blue hues. Ensure each portion is evenly colored with no streaks.
Press each colored mixture into the prepared pan, layering them in stripes or sections to create a patriotic appearance. Use a greased spatula or parchment paper to press firmly and evenly, smoothing the surface. The mixture should be compact and flush with the edges of the pan.
Allow the treats to cool completely at room temperature for about 15-20 minutes, or until firm. Once cooled, cut into rectangular bars or desired shapes and serve. Optionally, decorate with additional candies for festive flair.
