Step 1

First, make the crust: In the bowl of a food processor, pulse Oreo cookies to a very fine crumb. Transfer cookies to a medium bowl; add melted butter and stir until mixture is well-combined. Press the mixture evenly and firmly into the bottom and sides of a 9-inch pie plate (use the bottom of a dry measuring cup to press the crust down as much as possible). Transfer pie plate to the freezer to chill the crust while you make the filling.

Step 2

In a medium saucepan over medium heat, bring milk to a very gentle simmer. Add marshmallows; stir until just melted. Remove from heat; set saucepan aside to cool to room temperature, then transfer saucepan to the fridge until the mixture is fully cool, even slightly chilled.

Step 3

Remove saucepan from the fridge; whisk in peppermint extract and vanilla extract until combined, then whisk in 1 to 2 drops green food dye, if using. Set aside.

Step 4

In a separate large bowl using an electric hand mixer, beat heavy cream on high speed until stiff peaks form, about 3 to 5 minutes. Gently fold whipped cream into marshmallow mixture until just combined.

Step 5

Spoon and spread filling into chilled and set Oreo crust. Cover pie plate with plastic wrap and return to the freezer. Chill pie for at least 3 hours.

Step 6

Just before serving, top with more whipped cream and chopped Andes mints/Oreo cookies. Serve chilled. Store leftover pie, covered, in the freezer for up to 1 week.