01 - Line a 9x13 inch baking sheet with parchment paper.
02 - Melt 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 sheet and spread evenly to approximately 1/4 inch thickness. Refrigerate for 10 to 15 minutes until just set.
04 - Melt 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 quickly spread to cover it without melting the layer beneath.
06 - Evenly sprinkle the crushed peppermint candies over the white chocolate layer, pressing lightly to help them adhere.
07 - Refrigerate for at least 30 minutes until fully set.
08 - Lift the bark from the sheet using the parchment paper and break into irregular pieces by hand.