1. Slice onions at least 1/4 inches thick as shown. Coat with butter and/or oil.
2. Place in grill opposite the coals for about 10-15 minutes to brown slightly but remain firm.
3. Add some wood chunks or chips to the fire for a slight smoke.
4. Remove from grill and chop onions to desired size, large chunks or diced.
5. Add Beef Stock to pan. Add beer and your favorite Brandy or Whiskey (optional), Worcestershire sauce, and mustard.
6. Close grill cover and then slow simmer for about an hour or more.
7. Serve with shredded cheese on top and some fresh toasted bread or croutons.