Preheat oven to 350 degrees. Combine chocolate cookie crumbs and melted butter. Press mixture into a 9-inch pie pan. Bake for 7-10 minutes. Cool completely.

In a medium saucepan, combine marshmallows and milk over medium heat. Cook, stirring constantly, until melted and smooth.

Remove from heat and stir in chopped chocolate and mint extract until smooth; set aside.

With an electric mixer, beat cream and sugar until stiff peaks form. Set aside 2 1/2 cups of whipped cream.

Fold 1/4 of the remaining whipped cream into the chocolate mixture (it will still be warm). Then fold the chocolate mixture back into the remaining whipped cream.

Spread the chocolate mint filling into the cooled crust. Refrigerate for 30 minutes. Top the pie with the reserved whipped cream. Garnish with chopped Mint OREOs. Refrigerate for at least hours before serving.