1. Spread 1 pint of softened frozen vanilla yogurt in the bottom of the chocolate piecrust. Freeze until set. Remove from freezer. Spread 1/2 cup of the raspberry preserves evenly over top of frozen yogurt in crust; spread the remaining pint of softened frozen vanilla yogurt evenly over top of preserves. Freeze again until set. Remove from freezer. Spread top evenly with the remaining 1/2 cup preserves. Sprinkle 1/2 cup of crushed chocolate wafers over top. Return to freezer until solid. Makes 8 servings.