01 - Line a baking sheet with parchment paper or a silicone mat to prevent sticking.
02 - Melt the semisweet chocolate in a heatproof bowl over a pan of simmering water, or microwave in 30-second bursts while stirring each time, until completely smooth. Stir in ½ teaspoon peppermint extract.
03 - Pour the melted semisweet chocolate onto the prepared baking sheet and spread evenly into a rectangle approximately 9x12 inches.
04 - Melt the white chocolate using the same method as the semisweet chocolate. Stir in the remaining ½ teaspoon peppermint extract.
05 - Drop spoonfuls of the melted white chocolate over the semisweet base. Use a skewer or knife to swirl the two chocolates together, creating a marbled pattern.
06 - Immediately sprinkle the green M&Ms or mint candies, green sprinkles, and mini chocolate chips evenly across the surface while the chocolate is still melted.
07 - Gently press the toppings into the chocolate to ensure they adhere properly.
08 - Refrigerate the bark for at least 30 minutes until fully set and firm to the touch.
09 - Break or cut the chilled bark into pieces and serve immediately.