1/2 c. butter
1/4 c. brown sugar
1 egg yolk
1 c. flour
1 tsp. vanilla
1 egg white

Mix in usual manner (except egg white). Roll in balls. Beat egg white until frothy. Dip cookies in whites, then in sesame seed. Press down in center with thimble. Bake at 350 degrees until golden brown. Fill with jelly.