01 - Line a 9x13 inch baking sheet with parchment paper.
02 - Melt dark chocolate in a heatproof bowl over simmering water or in 30-second microwave intervals, stirring until smooth.
03 - Stir in 1/4 teaspoon peppermint extract into the melted dark chocolate.
04 - Pour dark chocolate onto the prepared baking sheet and spread evenly to a thickness of about 1/4 inch. Chill in refrigerator for 15 to 20 minutes until just set.
05 - Melt white chocolate using the same method as dark chocolate until smooth.
06 - Stir in remaining 1/4 teaspoon peppermint extract into melted white chocolate.
07 - Pour white chocolate over the set dark layer and spread gently and evenly.
08 - Sprinkle crushed peppermint candies evenly over the white chocolate and lightly press in with a spatula.
09 - Refrigerate for at least 30 minutes until completely firm.
10 - Break or cut into 16 pieces. Store in an airtight container at cool room temperature for up to two weeks.