Heat oven to 350 degrees. Lightly greas jelly roll pan (15 1/2x10 1/2x1). Mix sugar, margarine and egg yolk in large bowl. Stir in flour and cinnamon. Press in pan. Beat egg white and water until foamy; brush over dough. Sprinkle with walnuts. Bake 20 to 25 minutes or until very light brown. Immediately cut into about 3x1 inch strips. Cool on wire rack. Makes 3 1/2 dozen cookies. Gold Medal cookies and bars cookbook