In a large bowl, cream butter and sugar until light and fluffy. Beat in molasses and egg. Combine dry ingredients, gradually add to creamed mixture. Cover and refrigerate for 1 hour or until firm. Roll into 1-inch balls. Place 2 inches apart on greased baking sheets. Press flat with a glass dipped in sugar.
Bake at 375º for 8 to 10 minutes or until lightly browned. Remove to wire racks to cool. Sprinkle with more sugar if desired.