Line a baking sheet with parchment paper.
In a microwave-safe bowl, melt the semi-sweet chocolate chips in 30-second increments, stirring in between until smooth. Alternatively, use a double boiler. Pour the melted chocolate onto the prepared baking sheet and spread it evenly.
Place the baking sheet in the refrigerator for about 15-20 minutes, or until the chocolate sets.
Melt the white chocolate chips in the same way, adding the peppermint extract. Stir well.
Pour the melted white chocolate over the chilled semi-sweet layer. Quickly spread it evenly.
Sprinkle the crushed candy canes evenly over the white chocolate. Press them down gently.
Return the bark to the fridge for another 15-20 minutes, or until fully set.
Once firm, break the peppermint bark into pieces. Serve and enjoy!