Prepare the Baking Dish: Line a 9x9-inch baking dish or a baking sheet with parchment paper, leaving some overhang for easy removal.

Crush the Oreos: Place the Mint Oreo cookies in a zip-top bag and crush them into smaller pieces using a rolling pin or your hands. Alternatively, you can use a food processor for a finer crumb. Set aside a handful of crushed Oreos for topping.

Melt the Chocolate: In a microwave-safe bowl, combine the mint-flavored chocolate chips and, if using, the peppermint extract. Microwave in 30-second intervals, stirring between each interval until fully melted and smooth.

Combine with Oreos: Stir the crushed Oreos into the melted chocolate until well coated.

Spread the Mixture: Pour the mixture into the prepared baking dish and spread it out evenly with a spatula. Sprinkle the reserved crushed Oreos on top, pressing them gently into the chocolate.

Optional White Chocolate Drizzle: If you want to add a drizzle of white chocolate, melt the white chocolate chips in a microwave-safe bowl (using the same method as before) and drizzle over the top of the bark.

Chill: Place the baking dish in the refrigerator for about 30 minutes, or until the bark is set and firm.

Break into Pieces: Once set, remove the bark from the baking dish using the parchment paper overhang. Break it into pieces.

Serve and Store: Enjoy your Mint Oreo Bark! Store any leftovers in an airtight container at room temperature for up to a week.