Begin by lining a quarter sheet pan with parchment paper.
Melt the dark chocolate in a double boiler or microwave, stirring well between 30-second intervals. Once melted, immediately stir in ¼ teaspoon of peppermint extract.
Spread the melted dark chocolate evenly on the sheet pan. Place the tray in the refrigerator for 10-15 minutes until just set.
While the dark chocolate is setting, melt the white chocolate and stir in the remaining peppermint extract.
Once the dark chocolate layer is mostly set, spread the white chocolate over the top in an even layer.
Immediately sprinkle the crushed candy canes evenly over the white chocolate.
Place the bark in the refrigerator for at least 1 hour to fully set. Once set, break it into pieces using a knife or your hands. Store the pieces in a sealed container in the refrigerator.