1small bag of Oreoscrushed into fine crumbs for topping
Combine the marshmallows and half and half in the top of a double broiler OR in a microwave safe bowl. If using the double broiler cook, stir constantly until the marshmallows have melted completely. If using a microwave, cook in 30 second intervals on 50% power, stirring in between until marshmallows are melted completely when whisked.
Add the Cème de Menthe into the marshmallow mixture and whisk to combine. Allow the mixture to cool slightly, about 10 minutes.
Using a standing or hand held mixer, whip heavy whipping cream until firm peaks appear. Fold/stir into the green marshmallow mixture. Whisk lightly at the end as needed to ensure the mixture is completely combined.
Pour into the Oreo Cookie Pie Crust.
Sprinkle the remaining cookie crumbs on the top and place in the freezer.