Peel the onion, cut into fine cubes and sauté in butter until translucent. Let cool a little and mix with the minced meat. Knead the egg, mustard, breadcrumbs, parsley, garlic and diced bacon into the mince mixture. Season with maggi, pepper and salt. If desired, season with a little Worcester sauce.
Shape balls and flatten them a little.
Heat clarified butter, oil or oil with butter in a pan. Slowly fry the meatballs on both sides at a medium temperature until crispy.