1Spray 10-inch angel food (tube) cake pan or 12-cup fluted tube cake pan with cooking spray.
2In large microwavable bowl, microwave butter uncovered on High 30 to 60 seconds or until melted. Add marshmallows; toss to coat. Microwave on High 1 minute 30 seconds to 2 minutes, stirring every 30 seconds, until marshmallows are completely melted and mixture is well blended. Stir in cereal and candies until well coated. Press evenly into pan.
3Cool at room temperature until firm, about 1 hour. If necessary, run knife around edge of cake to loosen from pan. Turn cake upside down onto serving platter.