In a small skillet, cook the onion in the lard until translucent and it begins to brown around the edges. Meanwhile, in a large skillet with a lid, brown the ground beef. Drain it. Add the cooked onion with its juices. Stir in the celery, garlic, parsley, mint, lemon thyme, lemon pepper, mustard powder, seasoning salt, SteviaPlus, chili oil, and water or stock. Cover and simmer for 45 minutes to 1 hour. Just before serving add the arrowroot/water mixture to the boiling gravy and stir.