1Heat oven to 350°. Spray cookie sheet with cooking spray. Mix popcorn and cereal in large bowl; set aside.
2Microwave marshmallow creme in medium microwavable bowl uncovered on High 1 minute; stir. Microwave about 1 minute longer or until melted; stir. Pour over popcorn mixture, stirring until evenly coated. Spread mixture on cookie sheet.
3Bake 5 minutes; stir. Bake about 5 minutes longer or until coating is light golden brown. Spread on waxed paper or aluminum foil to cool. Store in tightly covered container up to 2 weeks.