Combine first 5 ingredients in a medium bowl; blend well. Press onto bottom and 2 inches up sides of a 10 inch springform pan. Bake at 350 degrees for 5 minutes. Cool on wire rack. Combine cream cheese and 1 cup sugar in a large mixing bowl; beat at medium speed of an electric mixer until fluffy. Add sour cream and vanilla; mix well. Stir in white chocolate. Beat egg whites (at room temperature) in a large bowl at high speed of an electric mixer until foamy; add cream of tartar, beating until soft peaks form. Fold egg whites into cream cheese mixture. Spoon mixture into crumb crust. Bake at 325 degrees for 55 minutes; turn oven off. Leave cheesecake in oven 30 minutes; partially open door of oven and leave cheesecake in oven an additional 30 minutes. Cool, chill 8 hours. Remove from pan. Yield 10-12 servings. ............ Debbie Holland, November 14, 1988 First used for Thanksgiving dinner. It is a time consuming recipe but worth the trouble! Taken from Southern Living magazine. ----