Combine ground beef, breadcrumbs, egg, milk, Worcestershire, ketchup, mustard, onion powder, garlic powder, salt, and pepper in a mixing bowl and form into 4-6 patties about ¾" thick (depending on how big you like your patties).
Melt butter in a cast iron skillet over medium heat. Brown patties for 3 minutes per side and remove to a plate while you make the gravy.
Reduce heat to medium low and melt butter. Add flour and whisk until combined and cook for 1 minute until it smells lightly toasted. Add in the ketchup, Worcestershire, and seasonings, whisking thoroughly.
Add the steaks back into the gravy pan and cook for 10 additional minutes (until internal temperature of 165℉). If you are using mushrooms, add them in now to cook the remaining time.
Serve with mashed potatoes and enjoy!