In a large bowl, combine all dry ingredients.In a smaller bowl, mix together the molasses, milk, and sourdough starterPour the liquid mixture into the dry ingredients. Stir to mix well.Grease the inside of 4 wide-mouth pint canning jars with butter.Divide the dough among the jars.Cover each jar with aluminum foil.Place jars in a canning basket. Lower basket into a water bath canner with boiling water. The water should be about â…” of the way up the jars.Reduce heat and steam bread for 1 - 1½ hours or until done. Check occasionally to make sure the canner doesn't boil dry.Remove from canner. Let cool slightly. Remove bread from the jars. You may need to run a butter knife down the side of the jar to gently dislodge the bread.Cool on a cooling rack.Sliced bread can be steamed to re-heat.Optional Steaming Directions:Use a large pot instead of the water bath steamer. Place something on the bottom of the pot to keep the jars off of the bottom, canning lids or crinkled aluminum foil or a steamer basket would work. Instead of canning jars use 4 clean, 15 oz cans.Optional Baking Directions:Spoon batter into a greased bread loaf pan. Bake at 325 degrees for one hour.