Combine first 5 ingredients in medium bowl; blend well. Press into bottom and 2" up sides of 10" spring form pan. Bake at 350 for 5 min. Cool. Combine cream cheese and 1 cup sugar; beat at medium speed until fluffy. Add sour cream and vanilla; mix well. Stir in melted white chocolate. Beat egg whites at high speed until foamy; add cream of tartar beating until soft peaks form. Fold egg whites into Cream cheese mixture; spoon into crust. Bake at 325 degrees for 55 minutes; turn oven off. Leave cheesecake in oven 30 min., open oven door and leave in an additional 30 minutes. Cool. Chill 8 hours. Remove from pan. Yield: 10 - 12 servings (From Andra Schabo)
