My husband's grandfather or Aunt Evvy's Father, worked a creamery business. This recipe is written on the back of a reciept for the creamery dated April 14, 1930. Aunt Evvy wrote a note on the bottom "This appears to be in my handwriting." 5/16/05 She would have been 17 at the time of "jotting" it down. There is also no mention of flour, and I think adding flour was "assumed". Many of Aunt Evvy's and her mother's recipes do not mention flour amounts.
1 cup sugar
1 cup molasses
1 cup shortening
1 egg
1 tablespoon soda
1 tablespoon ginger
some salt
7 tablespoons hot water
Mix & roll. A little down on the page she has a note "Not quite so much shortening"