Measure cereal into large mixing bowl. Set aside.
In small microwavable bowl, microwave chocolate chips, peanut butter and butter uncovered on High 1 minute; stir. Microwave about 30 seconds longer or until mixture can be stirred smooth. Stir in vanilla and peppermint extracts.
Pour melted chocolate mixture over cereal, stirring until evenly coated.
Pour into two 1-gallon resealable plastic bag, using FreezEasy bag holders.
Add powdered sugar. Seal bag; shake until well coated.
Spread on waxed paper to cool. Store in airtight container in refrigerator.