Cut off stem of peppers, then wash and de-seed them. In a medium sauce pan, boil 1 c. water and 1 1/2 t salt over high heat. When boiling, add peppers and cook for 5 minutes. Drain peppers of all water.
In a mixing bowl, blend together ground beef, tomato sauce, cracker crumbs, 1 t. salt, pepper and onion. Divide and stuff into the three peppers, placing them right side up (hole at the top) in a baking dish. Cover with foil and cook for 45 minutes in a 350 degree oven. Remove foil and cook for 15 minutes more. Makes 3-4 servings.