Start by melting the butter in a microwave-safe bowl. Once melted, set aside to cool for 5 minutes. (Hot butter causes a greasy crust.)
In a powerful blender or food processor, blend whole Mint Oreos (cookie and crème) until they are all crumbs. Re-blend any large chunks so the crust will cut nicely.
Measure once fully crumbled, then transfer the crumbs to a bowl. Save any remaining crumbs for a garnish. Add the melted (and slightly cooled) butter and a tiny pinch of salt. Stir until a thick dough forms and press that mixture into a pie pan.
Use the bottom of a 1/4-cup measuring cup to press the crust firmly into the bottom of the pan and up the sides. Place the crust in the freezer while preparing the filling.
Scoop in the entire container of softened mint chip ice cream into the chilled crust. Smooth the top of the ice cream evenly with the back of a large spoon or spatula.
Freeze for 30 minutes or until solid.
Remove from the freezer and smooth the hot fudge topping evenly over the ice cream.
Loosely cover and return to freezer for another 30 minutes.
Remove pie from freezer and smooth the frozen whipped topping over the chocolate fudge layer.
Sprinkle with any remaining cookie crumbs, if desired. Return to the freezer and freeze until very solid, about 4–8 hours.
Coarsely chop 3–5 leftover Mint Oreos and sprinkle over the pie. Cut into slices. If the pie is especially firm, let it stand for 5 minutes at room temperature before cutting and serving.