Line an 8-inch baking pan with aluminum foil, making sure the foil comes up along the sides. Smooth out any wrinkles in the foil to create an even surface. Set the pan aside for later use.

In a medium saucepan over low-medium heat, melt the semi-sweet chocolate, stirring constantly until completely smooth. Alternatively, you can microwave the chocolate in 15-second intervals, stirring between each interval until melted. Once smooth, stir in the peppermint extract thoroughly.

Pour the melted semi-sweet chocolate with peppermint from Step 2 into the prepared baking pan. Use a spatula to spread it into a thin, even layer. Rap the pan on the counter a few times to remove air bubbles. Crush 2/3 cup of mini pretzels into medium pieces and sprinkle evenly over the melted chocolate. Place the pan in the refrigerator or freezer for about 20 minutes or until the chocolate is completely set. I recommend letting the layer chill thoroughly to prevent the next layer from melting into it.

Once the semi-sweet layer is fully set, melt the white chocolate in a saucepan over low-medium heat, stirring constantly until smooth. Alternatively, use the microwave method as before. Pour the melted white chocolate directly over the set chocolate and pretzel layer, gently spreading with a spatula into an even layer. Be careful not to disturb the bottom layer, as it may melt slightly. Tap the pan gently on the counter to remove any air bubbles.

Crush the remaining 1 1/3 cup of mini pretzels into small pieces. Evenly sprinkle the crushed pretzels and all of the crushed candy canes over the wet white chocolate layer. Rap the pan again on the counter to help everything settle. Place the pan in the refrigerator or freezer until the entire bark is completely set. For extra festive flavor, I like to gently press the toppings into the chocolate before chilling to make sure they stick well.

Once the chocolate bark is fully hardened, carefully lift it out of the pan using the foil. Remove the foil and break the bark into pieces or cut into squares with a sharp knife. If cutting, let the bark sit at room temperature for about 10 minutes to avoid cracking. Enjoy your festive peppermint pretzel bark!