Line cookie sheet with waxed paper or cooking parchment paper. Spray large bowl with cooking spray; place cereal, peanuts and cranberries in bowl.

Spray medium microwavable bowl with cooking spray; add peanut butter, butter and marshmallows. Microwave uncovered on high 2 to 3 minutes or until smooth, stirring after each minute.

Pour hot marshmallow mixture over cereal mixture; stir until cereal is well coated. Drop mixture by rounded tablespoonfuls onto waxed paper. If mixture becomes hard to scoop, reheat in microwave 1 minute.

Cool completely, at least 1 hour. Store covered in airtight container at room temperature.