Mix ground beef, breadcrumbs, egg, garlic, seasoning, and Worcestershire sauce just until combined. Form into four patties.
Brown patties in a skillet over medium heat for about 3 minutes per side. Remove and set aside.
Add butter and onions to the skillet. Season with black pepper and cook over low to medium heat for 12–15 minutes until softened and lightly browned.
Stir in gravy mix and water. Cook until thickened.
Return patties to the skillet, spoon gravy over them, cover, and simmer on low for 10 minutes.
