01 - Line a 9x13 inch baking sheet with parchment paper.
02 - Melt the semisweet or dark chocolate in a heatproof bowl over simmering water or microwave in short bursts, stirring until smooth.
03 - Pour the melted dark chocolate onto the prepared sheet and spread evenly to about 1/4 inch thickness. Refrigerate for 15 minutes until just set.
04 - Melt the white chocolate using the same method. Stir in peppermint extract if using.
05 - Pour the melted white chocolate over the set dark chocolate layer and spread gently to cover evenly.
06 - Immediately sprinkle crushed peppermint candies evenly over the white chocolate, pressing gently with parchment paper if needed.
07 - Refrigerate for at least 1 hour until fully set.
08 - Break the bark into pieces and store in an airtight container at cool room temperature for up to 2 weeks.