For the crust: Preheat the oven to 350 degrees F. Process the cookies and granulated sugar in a food processor until finely ground. Add the melted butter and creme de menthe, and pulse until moist. Press the crumbs into a 9-inch pie plate, and bake until firm, 12 to 15 minutes. Let the crust cool completely on a wire rack.
For the filling: Microwave the marshmallows and butter in a microwave-proof bowl on high until the butter is melted and the marshmallows have broken down, about 1 minute 30 seconds. Stir with a wooden spoon to combine, and let cool for 5 minutes.
Beat the creme de menthe and heavy cream in a large bowl with an electric mixer on medium-high speed until fluffy peaks form, about 1 minute. Stop the mixer, add 1/3 of the cooled marshmallow mixture and beat on medium-high until combined, about 15 seconds; repeat with the remaining marshmallow mixture in 2 batches. (The whipped cream won't hold its peaks, and the cream-marshmallow mixture will appear quite loose, but it firms quickly as it cools in the pie crust.) Pour the filling into the prepared pie crust. Cover the pie with plastic, and refrigerate until firm, about 4 hours or overnight.
For the chocolate mint whipped cream: Beat the confectioners' sugar, cocoa powder and peppermint extract in a large bowl with an electric mixer on medium high speed until combined. Add the heavy cream, and beat on medium-high until fluffy peaks form.
To assemble: Arrange the wafer cookies on top of the pie. Top each cookie with 1/2 teaspoon creme de menthe (it will soak in almost immediately). Transfer the whipped cream to a pastry bag fitted with a large star tip, and pipe it onto the soaked cookies. Garnish with mint leaves. The pie can be refrigerated, loosely covered, up to overnight or served immediately. Serve with any extra leftover whipped cream on the side.
Copyright 2015 Television Food Network, G.P. All rights reserved.