Line a 9x13 baking pan with parchment paper.
Melt the dark or milk chocolate. I prefer to use a double boiler, but you can use the microwave as well. Once the chocolate is melted pour it onto the parchment paper and smooth it out. Set aside to harden, until firm. Which is about an hour at room temperature. Or a refrigerator for 20 minutes or freezer for 10 minutes.
While the milk/dark chocolate is hardening, crush up your candy canes or peppermints for your toppings.
Once the chocolate is hardened, melt the white chocolate. When it has melted add in ½ teaspoon of peppermint extract. Stir and then pour the melted white chocolate on top of the other layer and spread in an even layer.
Sprinkle the crushed candy canes on top of the white chocolate layer. Set aside at room temperature until firm, which is about an hour.
Break or cut the bark into pieces!