In a large bowl mix together the ground beef, soy sauce, garlic powder, onion powder, pepper, salt, bread crumbs and egg. Mix only until combined, don’t overmix. Shape into four equal patties.
In a large skillet over medium-high heat melt 2 tablespoons of butter. Add the ground beef patties and cook about 4 minutes on each side until browned (they will cook further in the sauce later). Remove from skillet and place on a plate.
Using the same skillet, reduce the heat to medium and add the remaining 2 tablespoons of butter. Add in the sliced onions and mushrooms and cook for 5 to 6 minutes or until softened and browned.
Add the garlic and cook for an additional minute.
Sprinkle the flour over the mushrooms, onions and garlic and stir while cooking for one minute.
Add the beef broth and Worcestershire sauce and salt and pepper to taste and cook for about 5 to 6 minutes stirring frequently.
Add the hamburger steaks back into the skillet (along with any juices on the plate) and cover them with the gravy.
Cover with a lid and reduce heat to a simmer and cook for another 10 minutes.
Remove lid and cook another 10 to 15 minutes letting the sauce thicken.
Garnish with chopped parsley.