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." 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"