Remove the ice cream from the freezer and let it soften slightly, about 5 minutes at room temperature.
Into the bottom of four parfait or ice cream dishes, scoop about 2 tablespoons of the vanilla ice cream.
Top with about 1/2 tablespoon of the cookie crumbs, and drizzle with 1 1/2 teaspoons of the liqueur. Continue layering the ingredients, ending with liqueur on top.
Serve immediately, garnished with the chopped nuts.
Yield: 4 servings