Line a large baking sheet with parchment paper or a silicone baking mat.

Place Oreo cookies in a zip-top bag and crush them into rough chunks with a rolling pin. Set aside.

Melt the white chocolate or candy melts in a microwave-safe bowl in 30-second increments at 50% power, stirring in between, until smooth.

Stir in the peppermint extract and green gel food coloring until the color is vibrant and uniform.

Fold 3/4 of the crushed Oreos into the melted green chocolate.

Spread the mixture evenly onto the prepared baking sheet, about 1/4 inch thick.

Sprinkle the remaining crushed Oreos over the top, pressing them in gently.

Chill in the refrigerator for 30-45 minutes until completely set, then break into pieces and serve.