In a large mixing bowl, combine ground beef, breadcrumbs, egg, whole milk, Worcestershire sauce, dried Italian seasoning, salt, and pepper. Mix gently until just combined, then form into approximately 15 meatballs.

Preheat a large skillet over medium-high heat, add oil, then carefully place in meatballs and sear for about 4-5 minutes, turning occasionally until browned on all sides. Remove and set aside.

In the same skillet, add sliced Vidalia onions and sauté for 5-10 minutes until soft and lightly caramelized.

Add butter to the onions and let it melt. Sprinkle in flour while stirring continuously to create a roux, then gradually add beef broth and water, whisking until smooth.

Return the meatballs to the pan, simmer for 10-15 minutes on low heat until cooked through and gravy thickens. Adjust consistency with water or broth if needed.

Taste the gravy and adjust seasoning as necessary, then serve with mashed potatoes, rice, or noodles, garnished with fresh chopped parsley if desired.