Line a baking sheet with parchment paper and set it aside.
In a microwave-safe bowl, melt the dark chocolate chips. Heat in the microwave in 30-second intervals, stirring after each interval, until fully melted and smooth.
Pour the melted dark chocolate onto the prepared baking sheet, spreading it evenly to form a rectangle about 1/4 inch thick. Place it in the refrigerator for about 10 minutes or until set.
While the dark chocolate is cooling, melt the white chocolate chips in a separate bowl using the same microwave method until smooth.
Once the dark chocolate has set, remove it from the refrigerator. Stir the peppermint extract into the melted white chocolate and pour it over the cooled dark chocolate layer. Spread it evenly with a rubber spatula.
Immediately sprinkle the crushed candy canes over the top of the white chocolate layer, pressing down lightly to ensure they adhere.
Return the baking sheet to the refrigerator and let the bark set completely, about 30 minutes.
Once set, remove the bark from the parchment paper and break it into pieces of your desired size.