01 -
Grab a square 8 or 9-inch pan and line it with wax paper. Leave extra paper hanging off the sides for lifting later. Spray the wax paper with cooking spray—it'll keep things from sticking when you take it out.
02 -
Toss the butter and mini marshmallows into a big microwave-safe bowl. Heat it for a minute, then stir well. Zap it again for another minute, stir again, and keep going in short bursts until it’s silky smooth. Don’t let it overheat—it’ll mess up the texture.
03 -
Scoop the melted stuff into six bowls equally—it’s about a cup per bowl. Add gel coloring to each one for your rainbow: purple, red, orange, yellow, green, and blue. Stir well so the colors mix nicely, tweaking intensity if needed.
04 -
Take one colored bowl at a time and add 2½ cups of crisped rice cereal to it. Coat a spatula with spray oil, then gently stir the cereal until it’s all covered evenly. Don’t leave any dry bits!
05 -
Start stacking the colors in the prepared pan. Gently press the purple layer at the bottom using an oiled spatula or wax paper. Keep adding layers in this order: blue, green, yellow, orange, red. Push gently so the layers stick but don’t smash them down too tight.
06 -
Let the pan sit on the counter and cool completely, which usually takes about half an hour. Don’t stick it in the fridge or the layers might get hard instead of staying chewy.
07 -
Once cooled, lift the whole colorful block out of the pan using the wax paper overhang. Move it to a cutting board. Trim uneven edges if you want, then cut it into 1-inch squares with a buttered knife for clean slices.
08 -
To make them look fancy, melt almond bark or white candy melts as per the directions and drizzle over the top. Let it harden before serving.
09 -
Lay out your colorful treats on a platter to serve, or stack them in an airtight container with wax paper in between to keep them from sticking together.