Grease an 8-inch baking pan/dish with butter or cooking spray. Set aside.

In a large saucepan, melt the butter over medium heat. When melted add the marshmallows and cook for 1-2 minutes, stirring constantly with a spatula/wooden spoon, until completely melted.

Remove from the heat and stir in half of the crushed peppermint and Oreos, then stir in the cereal.

Turn the mixture out into the prepared baking dish. Using a sheet of wax paper or greased parchment, press the mixture into an even layer. (Make sure you get into the corners, people!) Sprinkle the top with the remaining Oreos and peppermint and use the paper to press the toppings into the Rice Krispie treats.

Place the white chocolate and the dark chocolate in separate microwave-safe bowls. Microwave in 15-second intervals, stirring after each one, until the chocolate is melted. (It shouldn’t take more than a minute, tops.) Drizzle the white chocolate over the Rice Krispie treats. (It will be a little gloppy. That’s okay!!) Repeat with the dark chocolate.

Refrigerate the treats for 25-30 minutes until the chocolate sets. Slice into 9 squares (or 12 rectangles) and get festive.