01 - Line a 9x13 inch baking sheet with parchment paper.
02 - Melt the dark chocolate in a heatproof bowl over barely simmering water or in the microwave in 30-second intervals, stirring until smooth. Stir in 1/4 teaspoon peppermint extract.
03 - Pour the melted dark chocolate onto the prepared baking sheet, spreading into an even 1/4-inch thick layer. Chill in the refrigerator for 10 to 15 minutes until just set.
04 - Melt the white chocolate using the same method as the dark chocolate. Stir in the remaining 1/4 teaspoon peppermint extract.
05 - Pour the melted white chocolate over the set dark chocolate layer and spread gently and quickly to cover evenly, preventing melting of the layer beneath.
06 - Sprinkle crushed peppermint candies evenly atop the white chocolate, pressing lightly to adhere.
07 - Refrigerate for at least 30 minutes until fully firm.
08 - Lift the bark from the pan using parchment paper and break into irregular shards by hand.