The recipe yield is:
1. In a bowl, beat butter and sugar until smooth. Mix in flour, vanilla, and egg whites until smooth. 2. Bake 2 cookies at a time. Butter a 12x15" baking sheet. With fingertip, draw a 7" wide circle on 1 corner of sheet; repeat in opposite corner. In each circle, spread 3 tablespoons batter to fill evenly. 3. Bake in a 350'F. oven until golden, 9-10 minutes. At once, lift cookies, 1 at a time, with wide spatula and drape each over a clean 1 pound food can; gently pinch cookie sides to form a fluted cup. Repeat to make remaining cookies. If made ahead, store ahead up to 1 day. Makes 6.