PREHEAT oven to 325°F if using a silver 9-inch springform pan (or to 300°F if using a dark nonstick 9-inch springform pan). Mix crumbs, 3 Tbsp. of the sugar and butter; press firmly onto bottom of pan. Bake 10 minutes.

BEAT cream cheese, 3/4 cup sugar, lemon zest, juice and 1/2 tsp. of the vanilla with electric mixer on medium speed until well blended. Add eggs, 1 at a time, beating on low speed after each addition just until blended. Pour over crust.

BAKE 55 minutes to 1 hour or until center is almost set. Mix sour cream, remaining 3 Tbsp. sugar and remaining 1 tsp. vanilla until well blended; carefully spread over cheesecake. Bake an additional 10 minutes. 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.