In a mixing bowl, combine ground beef, chopped onion, egg, breadcrumbs, Worcestershire sauce, salt, and black pepper.
Mix gently and shape into 4 oval patties.
Heat olive oil in a large skillet over medium heat.
Cook patties for 4–5 minutes per side until browned, then remove and set aside.
Add sliced onions to the same skillet and cook until soft and caramelized.
Sprinkle flour over onions and stir well.
Slowly pour in beef broth while stirring to form gravy.
Add soy sauce and bring gravy to a gentle simmer.
Return patties to the skillet and spoon gravy over them.
Simmer for 10 minutes until patties are cooked through.
Remove from heat and let rest for 5 minutes before serving.