Step 1: Line a large baking sheet (about 10×15 inches) with parchment paper. This will prevent sticking and make for easy removal.
Step 2: Melt the dark chocolate using a double boiler method. Place a heatproof bowl over a saucepan with an inch or two of simmering water, ensuring the bowl does not touch the water. Add three-quarters of the chopped dark chocolate to the bowl and stir until mostly melted and smooth. Remove from heat and stir in the remaining chocolate until fully melted and glossy. This helps temper the chocolate for a better snap and shine.
Step 3: Pour the melted dark chocolate onto the prepared baking sheet and spread it evenly into a thin layer, about 1/8 to 1/4 inch thick, using an offset spatula or the back of a spoon. Refrigerate for 15-20 minutes, or until completely set.
Step 4: While the dark chocolate is chilling, melt the white chocolate using the same double boiler method. Once smooth and melted, remove from heat and stir in the peppermint extract. Taste and add more extract if you prefer a stronger peppermint flavor.
Step 5: Remove the set dark chocolate from the refrigerator. Pour the peppermint white chocolate over the dark chocolate layer, spreading it gently and evenly to cover the entire surface without disturbing the bottom layer.
Step 6: Immediately and generously sprinkle the crushed candy canes over the wet white chocolate layer. Gently press them into the chocolate to ensure they adhere.
Step 7: Return the baking sheet to the refrigerator for at least 30-60 minutes, or until both chocolate layers are completely firm and hard. For storage, you can use airtight containers. I personally recommend Basics Glass Food Storage to keep it fresh for longer.
Step 8: Once fully chilled, lift the bark off the parchment paper and place it on a clean cutting board. Using a large, sharp knife or your hands, break the bark into irregular pieces of various sizes. Store in an airtight container at cool room temperature or in the refrigerator for up to 2-3 weeks.