In a large bowl, mix together the ground beef, breadcrumbs, egg, Worcestershire sauce, ketchup, onion powder, garlic powder, salt, and pepper. Form into 4–6 oval patties.

Heat the olive oil in a skillet over medium-high heat. Sear the patties for about 4 minutes per side until they are browned. Remove and set aside.

In the same skillet, add the unsalted butter, sliced onions, and mushrooms. Sauté over medium heat for 8–10 minutes until caramelized.

Stir in the beef broth, Worcestershire sauce, and ketchup. Bring to a simmer.

Mix cornstarch with cold water to form a slurry. Whisk into the gravy until thickened.

Return the patties to the pan, cover partially, and simmer for 15–20 minutes until fully cooked.

Adjust seasoning, garnish with parsley if desired, and serve over mashed potatoes, noodles, or rice.