On a square piece of aluminum foil place a hamburger patty. Top with sliced onion, potatoes, carrots, some celery, peas and maybe some baked beans. Fold foil together and seal to keep moisture in. Place on cookie sheet or foil pie pan. Bake in a 350 degree oven for about 45 minutes. Unfold foil very carefully to check to see if all ingredients are cooked to your required doneness. If not, recover and cook a bit longer. An easy and quick supper dish, served with a salad or cottage cheese. May even be made ahead.