Combine the meatball ingredients in a large bowl and mix well.
Heat large pan to medium high and add oil. Form into desired meatball size and start browning them on most sides until almost cooked, about ten minutes. Remove from pan and set aside, leaving the fat in the pan.
Add butter and onions to the pan and cook until soft, about 5 minutes.
Add beef broth, Worcestershire sauce and season to taste with salt and pepper. Add xanthan gum and mix well.
Return meatballs to pan and cook another 15 minutes turning the meatballs once, until fully cooked and the sauce is thickened. Enjoy!