In a large bowl, combine ground beef, breadcrumbs, egg, ketchup, Worcestershire sauce, diced onion, garlic, salt, and pepper. Mix gently until just combined - avoid overworking the meat.

Shape the mixture into 6-8 oval patties, about 1-inch thick. Create a slight indentation in the center of each patty to prevent bulging during cooking.

Heat a large skillet over medium-high heat. Cook the patties for 4-5 minutes on each side until browned. Transfer to a plate and set aside.

In the same skillet, melt butter. Add mushrooms and onions, cooking until softened and golden (about 8-10 minutes).

Sprinkle flour over the mushrooms and stir constantly for 1 minute.

Gradually add beef broth while stirring continuously to prevent lumps. Add Worcestershire sauce and bring to a simmer.

Return the steaks to the skillet, reduce heat to low, and let them simmer in the gravy for 10-12 minutes until fully cooked.