PREHEAT oven to 350°F if using a silver 9-inch springform pan (or to 325°F if using a dark nonstick 9-inch springform pan). Mix baking crumbs and butter; press firmly onto bottom of pan.
BEAT cream cheese, sugar and vanilla in large bowl with electric mixer on medium speed until well blended. Add melted chocolate and liqueur; mix well. Add eggs, 1 at a time, mixing on low speed after each addition just until blended. Pour over crust.
BAKE 45 to 50 min. or until centre is almost set. Run knife or metal spatula around rim of pan to loosen cake; cool before removing rim of pan. Refrigerate 4 hours or overnight. Store leftover cheesecake in refrigerator.
serving size = 1 slice