In a large mixing bowl, combine ground beef, onions, eggs, bread crumbs, salt, pepper, and sage and mix together well. Form mixture into about 2" meatballs, roll in flour and brown well in small amount of oil in bottom of 12-inch Dutch oven. Flatten meatballs slightly as you put them in the oil; this should make 15-20 meatballs. After browning remove from oven and set aside.
Slice all potatoes about 1/4 inch thick, place in oven and stir in with meat drippings. (Potatoes can be used with or without skins; scrub well if you choose to leave the skin on). Pack potatoes down in bottom of oven evenly and place meatballs on the top. Mix mushroom soup, sour cream, and milk together and pour evenly over top of meal; cover and cook.
Start with 16 briquettes on the bottom of the Dutch oven to brown the meat. After combining all ingredients, use 10 briquettes below and 14 on the lid. Allow the dish to cook for an hour.