8 ounces bittersweet or semi-sweet chocolate
6 ounces white chocolate
½ teaspoon peppermint extract, divided
12 candy canes, crushed
Line a square or rectangular baking dish with foil. Melt the bittersweet chocolate in a microwave or in the top of a double boiler. Mix in 1/4 teaspoon of the peppermint extract. Spread the chocolate in the bottom of your prepared dish. Sprinkle the top of the chocolate with half the crushed candy canes. Put the dish in the freezer for a few minutes, but don't let it set completely.
In the meantime, melt the white chocolate and mix in the remaining peppermint extract. Once the bottom layer is firm, spread the white chocolate on top, being careful not to swirl the layers. Sprinkle the remaining candy cane pieces on top and gently pat them into the top layer.
Put the entire dish back in the freezer and leave it there until the candy is very firm. Once it's frozen, remove it from the dish, peel off the foil and snap the candy against a cutting board or counter edge to break into pieces.