Cream 1 cup brown sugar and 1 cup white sugar with 1 cup softened butter. Add two beaten eggs and a teaspoon vanilla extract; mix well. Then work in 3 cups flour that have been sifted with a teaspoon of baking soda. When thoroughly blended, refrigerate for an hour, then roll out on a floured board, cut into rounds, place on a flat, heavy baking sheet, and place in a 350-degree oven for 8 to 10 minutes. Cool thoroughly before serving.