Line a small rimmed baking sheet or 8×8 square baking dish with parchment paper or foil and set aside.

Fill a large sauté pan with a few inches of water and bring to a simmer over medium heat, then reduce the heat to low. This is your double boiler.

Place the bittersweet chocolate into a heat proof bowl and place the bowl in the pan of simmering water. Stir the chocolate as it melts, scraping down the sides of the bowl. When the chocolate is completely melted, remove from heat and stir in half of the crushed peppermint candy. Pour the chocolate onto the prepared pan and spread out to about 1/4" thickness, then place in the refrigerator for about 10-15 minutes or until nearly set.

Once the dark chocolate has set, repeat the same steps for the white chocolate. When the white chocolate is completely smooth, remove the dark chocolate layer from the refrigerator. Pour the white chocolate over the dark chocolate, and spread evenly over the top, being careful not to swirl the layers. Sprinkle the top with the remaining peppermint candy and return to the refrigerator for 30 minutes to set.

Once the bark has set, remove it from the refrigerator and let it stand for 15-20 minutes or so to come to room temperature before cutting as the layers can separate if it's too cold. From there, remove the bark from the pan and place on a cutting board. Using the tip of a sharp knife, cut the bark into pieces. When the tip of the knife is inserted, the bark breaks on its own. Serve and enjoy!