Microwave candy coating in a 1-qt. microwave-safe glass bowl at MEDIUM (50% power) 1 minute; stir. Microwave until melted and smooth, stirring at 30-second intervals. Stir in peppermint extract.

Spread half of melted candy coating about 1/8 inch thick in a parchment paper-lined jelly-roll pan. Sprinkle 1 cup chopped pretzels and 1/3 cup chopped M&M Peppermint candies over melted candy coating, and press into coating. Repeat procedure with remaining ingredients on another parchment paper-lined jelly-roll pan. Sprinkle with remaining chopped M&M Peppermint candies. Chill 5 minutes or until cool and firm. Break into pieces.