Cream together margarine and sugar thoroughly. Heat molasses to almost boiling and pour over margarine mixture. Mix in vinegar. Cool to lukewarm. Add egg.
Sift together flour, baking soda, salt, cinnamon, ginger. Add to cooled molasses mixture, stir together well to form dough. Chill dough overnight.
Preheat oven to 350. Roll out dough to about -inch thickness and cut into desired shapes. Decorate as desired. Bake for 8-10 minutes. Do not over-bake.