Line a 9x13 inch baking sheet with parchment paper and set aside.
Melt the dark chocolate in a double boiler or microwave in 30-second intervals, stirring between each until smooth. Stir in 1/2 teaspoon peppermint extract.
Pour the dark chocolate onto the prepared baking sheet and spread evenly to about 1/4-inch thickness. Refrigerate for 20 minutes until firm.
Melt the white chocolate the same way as the dark chocolate and stir in the remaining 1/2 teaspoon peppermint extract.
Pour the white chocolate over the hardened dark chocolate layer and spread evenly. Immediately sprinkle the crushed candy canes over the top, gently pressing them into the chocolate.
Refrigerate for at least 1 hour until completely set. Break into irregular pieces and store in an airtight container in the refrigerator for up to 2 weeks.