Line a baking sheet (about 9x13 inches) with parchment paper or a silicone baking mat. This will prevent the bark from sticking and make for easy removal.

In a microwave-safe bowl, melt the dark chocolate in 30-second intervals, stirring in between until smooth. Be careful not to overheat; you want it just melted and glossy.

Pour the melted dark chocolate onto the prepared baking sheet. Using a spatula, spread it into an even layer about 1/4 inch thick. Place the baking sheet in the refrigerator for about 15-20 minutes, or until the dark chocolate is set.

While the dark chocolate is setting, melt the white chocolate in a separate microwave-safe bowl using the same method (30-second intervals, stirring until smooth). Once melted, stir in the peppermint extract to give it that festive flavor.

Remove the baking sheet from the refrigerator and pour the melted white chocolate over the set dark chocolate layer. Use a spatula to spread it evenly over the dark chocolate.

While the white chocolate is still warm, sprinkle the crushed candy canes evenly over the top, pressing them down gently to ensure they adhere.

Return the baking sheet to the refrigerator for another 30 minutes, or until the white chocolate is fully set.

Once set, remove the bark from the refrigerator and lift it out of the baking sheet using the parchment paper. Break the bark into pieces of your desired size.