Stir flour with ginger, cinnamon, allspice, salt and baking soda in a large bowl. Beat butter with brown sugar in a large bowl, using an electric mixer on medium, for 2 min.
Beat in egg and molasses. Scrape molasses mixture into flour mixture. Beat, on low speed, until all flour is add for minutes and dough is no longer sticky but still soft. Roll into small balls, and then use fork dipped in sugar to press down. Bake at 350 for 7-9.