1. Put all ingredients in a bowl that's been sprayed with cooking spray.
2. Place in the microwave and heat on high for 45 seconds.
3. Remove from microwave stir to coat cereal with melted marshmallow and place mixture in a cupcake mold. Smoosh down so that the treat gets completely molded together but not enough to crush the cereal.
4. Remove from cupcake mold and gobble up.