01 - Line a 9x13-inch baking sheet with parchment paper, ensuring complete coverage to prevent sticking.
02 - Place chopped dark chocolate in a heatproof bowl set over a pot of gently simmering water, stirring continuously until completely smooth and glossy. Alternatively, microwave in 20-second intervals, stirring between each burst.
03 - Remove the melted dark chocolate from heat source and immediately stir in the peppermint extract until evenly distributed.
04 - Pour the seasoned dark chocolate onto the prepared baking sheet. Using an offset spatula, spread into a uniform rectangle approximately 1/4 inch thick, ensuring even coverage.
05 - Melt the white chocolate using the same double boiler method or microwave technique, stirring until completely smooth and fluid.
06 - Drop spoonfuls of melted white chocolate randomly over the dark chocolate base. Using a skewer or toothpick, gently swirl through both chocolates in circular or linear motions to create a marbled pattern.
07 - Immediately sprinkle crushed peppermint candies and mini chocolate chips over the surface while chocolate is still melted. Press lightly with fingertips to ensure toppings adhere properly.
08 - Transfer the baking sheet to the refrigerator and chill for at least 1 hour, or until the bark is completely firm and breaks cleanly when tested.
09 - Break the chilled bark into irregular pieces of desired size. Serve immediately or store in an airtight container at cool room temperature for up to 2 weeks.