Cream butter and sugar. Add beaten egg yolk. Mix flour and cinnamon. Lightly butter 10x15 inch baking pan. Spread on mixture covering pan. Brush slightly beaten egg white over batter. Sprinkle with pecans, pat lightly. Bake for 30 minutes at 325 degrees. Cut into bars when warm. Do not remove from pan until cool. For a crisper cookie, use the same recipe, but only use 1 cup flour and 3 teaspoon cinnamon.