Heat oven to 325°F. In medium bowl, combine crust ingredients; mix well. Press mixture in bottom and 2 inches up sides of ungreased 10-inch springformpan.
In large bowl, beat eggs. Add cream cheese and sugar; beat until smooth. Add 2 cups sour cream; blend well. Divide mixture in half. Stir 3 oz. melted chocolate and creme de cacao into half of mixture; pour into crust-lined pan. Stir creme de menthe into remaining mixture. Carefully spoon over chocolate mixture.
Bake at 325°F. for 65 to 80 minutes or until center is set. (To minimize cracking, place shallow pan half full of hot water on lower oven rack during baking.) Cool 2 hours or until completely cooled.
In small bowl, combine topping ingredients; mix well. Spread over top of cooled cheesecake. If desired, make spiral design with frosting comb or fork. Refrigerate at least 4 hours or overnight.
Just before serving, carefully remove sides of pan. Store in refrigerator.