Mix graham crumbs, 3 Tbsp. sugar and butter; press onto bottom of 9-inch springform pan.
Beat cream cheese, 1 cup sugar and vanilla with mixer until blended.
Add eggs, 1 at a time, mixing on low speed after each just until blended.
Pour over crust.
Bake 55 min. or until center is almost set. Run knife around rim of pan to loosen cake; cool before removing rim. Refrigerate cheesecake 4 hours.
Microwave COOL WHIP and chocolate in microwaveable bowl on HIGH 2 to 2-1/2 min. or until chocolate is completely melted and mixture is well blended, stirring after each minute. Cool 15 min.; slowly pour over cheesecake.