Combine all of the meatball ingredients except for the avocado oil in a medium bowl and mix thoroughly. Form into 15 meatballs. Heat the oil in a nonstick frying pan and cook the meatballs for 2-3 minutes per side or until browned on all sides. Remove the meatballs from the pan. Add the butter and onions to the same pan you cooked the meatballs in and cook for about 5 minutes until softened and just starting to brown. Season with salt and pepper, then pour in the stout (or other liquid) and sweetener. Add the meatballs in and stir well until coated.Cover and simmer for 20 -- 30 minutes. Remove the cover and simmer another 5-10 minutes or until the gravy has reduced a bit. Remove from the heat and stir in the 2 Tbsp butter until smooth. Serve hot garnished with parsley (optional) over Better Than Potatoes Cauliflower Puree if desired.