Mix the minced beef and sausage meat. In a pan, fry the onion for 3 or 4 minutes in a little oil. Add the onion, parsley, egg, salt, and pepper to the meat. Mix well with your hands. Make small balls of 4 cm with this mixture. Coat the albondigas (balls) in flour. In a clay pot, heat 4 tablespoons of oil and add the albondigas and white wine, cook for 5 minutes. Add the tomato sauce and cook for 15 minutes over low heat. From time to time, with a spoon, take some tomato sauce from the bottom of the pot and pour it over the albondigas. Serve hot. Pierce each albondiga with a toothpick.