01 - In a bowl, mix ground beef, breadcrumbs, egg, milk, salt, and pepper until well-combined. Form into 4-6 evenly sized patties.
02 - Heat a skillet over medium heat and brown patties on both sides. Remove and set aside.
03 - In the same skillet, sauté onions until soft and translucent. Sprinkle flour over onions and cook for 1 minute, stirring constantly.
04 - Gradually stir in beef broth, Worcestershire sauce, and thyme. Bring mixture to a simmer, stirring occasionally.
05 - Return patties to skillet, cover, and simmer for 15 minutes, or until meat is cooked through and gravy has thickened.