Microwave white chocolate chips in large microwaveable bowl on HIGH until almost melted, about 1 1/2 minutes, stirring after every 20 seconds. Remove bowl from microwave and stir until chocolate is completely melted and mixture is smooth. Stir in peppermint extract.
Spread on large foil-lined baking sheet to 1/4-inch thickness. Add food color, drop by drop, over mixture. Using a wooden skewer, swirl color through chocolate. Sprinkle with crushed candies, pressing lightly into chocolate with spatula.
Refrigerate about 10 minutes or until firm. Break into irregular pieces to serve. Store in covered container at cool room temperature or in refrigerator up to 5 days.