Scald 4 cups of the milk and place in a double boiler. Add the cornmeal and cook for 20 minutes. Mix molasses, ginger, salt, and butter; add to the cornmeal-milk mixture. Pour mixture into a baking dish. Pour remaining milk over the pudding. Bake in a 325 degree oven for 3 to 4 hours. Serve with whipped cream, hard sauce, or vanilla ice cream if you want.