Preheat oven to 350 degrees F.
Combine crushed cookie wafers with melted butter and press onto bottom and up sides of a 9-inch pie pan. Bake in oven for 10 minutes. Let cool.
Combine softened ice cream and 5 tablespoons coffee-flavored liqueur using a stand mixer or hand mixer until creamy. Fill pie crust with ice cream mixture, cover with plastic wrap and place in freezer for 3 to 4 hours.
Whip heavy cream with powdered sugar until soft peaks form. Top frozen pie with whipped cream. Refreeze for 1 hour.
Combine remaining tablespoon of coffee-flavored liqueur with hot fudge sauce, drizzle over top of pie and serve.