Combine crumbs, pecans, granulated sugar and margarine; press onto bottom of 9-inch springform pan. Bake at 325 degrees F., 10 minutes. Combine cream sheese and brown sugar, mixing at medium speed on electric mixer until well blended. Add eggs, one at a time, mixing well after each addition. Blend in chocolate and liqueur; pour over crust. Bake at 325 degrees F., 35 minutes. Increase oven temperature to 425 degrees F. Combine sour cream and granulated sugar; carefully spread over cheesecake. Bake at 425 degrees F. 10 minutes. Loosen cake from rim of pan; cool before removing rim of pan. Chill. VARIATION: Substitute 2 Tablespoons milk and 1/4 teasponn almond extract for almond flavored liqueur. Recipes from Nestles Toll House cookbook and Kraft Philidelphia Cream Cheese Cookbooks. File ftp://ftp.idiscover.co.uk/pub/food/mealmaster/recipes/chscake.zip