Combine crushed cookies with 1/3 cup melted butter. Press into a 13 x 9 x 2 inch pan. Spread with softened ice cream. Cover and freeze. Melt chocolate and butter over low heat. Add sugar, salt and milk. Cook and stir until thickened. Remove from heat and add vanilla.
Chill completely until cold. Spread on top of ice cream layer and return to freezer. Combine thawed whipped topping with liqueur. When chocolate layer is frozen, spread with whipped topping mixture. Sprinkle with nuts and freeze. Remove dessert from freezer a few minutes before serving to make cutting easier.
