Preheat your oven to 375°F (190°C) and spray a 9 x 13 inch baking pan with non-stick cooking spray.

In a food processor, finely crush the Oreos until they resemble sand. Combine with melted butter and press firmly into the bottom of the pan. Bake for about 8 minutes and cool completely.

In a mixing bowl, beat together softened cream cheese and powdered sugar until smooth. Fold in Cool Whip and spread over the cooled Oreo crust.

In another bowl, whisk milk and pudding mix until thickened. Fold in remaining Cool Whip, mint extract, and green gel food coloring.

Spread the mint-flavored pudding mixture over the cheesecake layer, smoothing it out. Sprinkle additional crushed Oreos on top if desired.

Cover with plastic wrap and chill in the refrigerator for at least 4 hours or until set. Slice into squares and serve chilled.