In a large bowl combine ground pork, ground beef, onion, egg, salt, pepper, breadcrumbs, nutmeg, allspice, and parsley. Mix the ingredients thoroughly then roll into 1 1/2 inch balls.Place butter in a large skillet and, working in batches, begin frying the meatballs, cooking them on all sides until they are perfectly browned and cooked through, about 10 minutes.Once meatballs are cooked set them to the side and begin making your sauce. Add butter to the skillet and once it is melted add the flour whisking quickly and forming a roux. Cook for 1-2 minutes or until it begins to turn a golden color.Slowly add beef broth whisking the whole time to keep it from getting lumpy. Once all of the broth has been added cook for 5-7 minutes or until the sauce begins to thicken.Add Worcestershire and heavy cream and continue cooking until the sauce is thickened enough to coat the back of a spoon.Add the meatballs to the sauce and cook them together for about 5 minutes.Serve over egg noodles or mashed potatoes.If your skillet has too many burned bits after you finish cooking the meatballs you can wash it out before starting your sauce.