In a medium bowl, cream together margarine and 1 cup white sugar until smooth. Beat in the egg and molasses until well blended. Sift together the flour, ginger, cinnamon, baking soda and salt then stir into the molasses mixture to form a dough. Roll dough into 2 1/2cm balls and roll the balls in the remaining sugar. Place cookies 5cm apart on ungreased baking trays.
Bake for 8 to 10 minutes. Allow biscuits to cool on baking tray for 5 minutes before removing to a wire rack to cool completely.