Cream sugar and butter. Mix oatmeal, baking soda and flour. Add to sugar; mix well. Form into walnut-sized balls. Place on ungreased baking sheet. Butter bottom of glass, dip in sugar and mash balls flat. (Redip in sugar as needed.) Bake in 350-degree oven 10 to 12 minutes. Cool 1 minute on cookie sheet then remove with spatula. Cool.