Beat cream cheese in large bowl of electric mixer until creamy. Add
sugar; beat until well blended. Add sour cream and vanilla; mix
well. Add eggs, one at a time, mixing on low speed after each
addition just until blended. Stir in melted chocolate. Pour batter
Bake 325 degrees for 30-40 minutes or until center is almost set.
Refrigerate 4 hours or overnight.