Grease bottom of 9-inch springform pan. Prepare cake mix as directed on package; pour batter evenly into springform pan. Bake at 325°F for 25 minutes if using a silver springform pan. (Bake at 300°F for 20 minutes if using a dark nonstick springform pan.) Cool.
Beat cream cheese, granulated sugar and 1 tsp. of the vanilla with electric mixer on medium speed until well blended. Add eggs, 1 at a time, mixing on low speed after each addition just until blended. Blend in sour cream; pour over cake layer.
Bake at 325°F for 40 to 45 minutes or until center is almost set if using a silver springform pan. (Bake at 300°F for 40 to 45 minutes or until center is almost set if using a dark nonstick springform pan.) Run knife or metal spatula around rim of pan to loosen cake; cool before removing rim of pan.
Place chocolate, milk and butter in medium microwavable bowl. Microwave on HIGH 2 minutes or until butter is melted, stirring after 1 minute. Stir until chocolate is completely melted. Add powdered sugar and remaining 1 tsp. vanilla; mix well. Spread over cooled cheesecake. Refrigerate 4 hours or overnight.
Makes 12 servings.
To soften cream cheese, place completely unwrapped package of cream cheese in microwavable bowl. Microwave on HIGH 15 seconds. Add 15 seconds for each additional package of cream cheese.
Date: August 11, 2002