1. Preheat oven to 325° F.
2. In small bowl toss together graham crumbs, margarine or butter, and 2 Tbs. sugar. Reserve 2 Tbs. of crumb mixture for garnish. Press remaining crumb mixture onto bottom and 2 1/4 inches up sides of 9-inch springform pan. Chill in freezer while preparing filling.
3. In large mixing bowl beat cream cheese on medium speed of electric mixer until fluffy. Add 1 1/3 cups sugar, cornstarch, and vanilla. Beat until combined. Add eggs, one at a time, beating until just combined after each addition. Stir in sour cream.
4. Pour into crust. Bake at 325° F about 1 1/4 hours or until center is almost set. Cool on wire rack for 15 minutes. Loosen sides of pan. Continue cooling on wire rack for 45 minutes more.
5. Sprinkle top with reserved crumbs. Refrigerate at least 3 hours. Garnish as desired. Store in refrigerator.