To make the steaks, combine the egg, breadcrumbs, ketchup, Worcestershire sauce, mustard powder, salt, garlic powder, onion powder, and black pepper and stir together with a fork until well combined. Add the ground beef and mix together until well combined. Use your hands to form the meat mixture into four patties.
Drizzle a large sauté pan with a tablespoon of olive oil and bring the pan over medium heat. Lay the patties in the pan in a single layer and cook for 3-5 minutes until the bottom is golden. Flip and cook for another 3-5 minutes until the patties are cooked through. Remove to a side plate and cover.
To make the mushrooms, add two teaspoons of olive oil to the sauté pan over medium heat. Add the sliced mushrooms and stir to toss in the oil before spreading across the surface of the pan. Cook, stirring occasionally, for 5-6 minutes until the mushrooms are softened and golden around the edges. Add the minced garlic. Stir together and cook for another 30-60 seconds until the garlic is fragrant. Remove the contents of the pan to the side plate with the meat and re-cover to keep warm.
To make the gravy, add the three tablespoons of light butter to the sauté pan and bring over medium-low heat until melted. Add the flour and whisk to combine (it will make sort of a paste – don’t worry about anything stuck to the bottom of the pan from previous steps, it will come up when you add liquid). Whisk in the broth a little at a time, stirring to combine as you go so that the flour dissolves into the broth and you scrape up anything stuck to the pan. Add the Worcestershire sauce, Better Than Bouillon, and the Gravy Master and whisk into the sauce. Raise the heat to bring the sauce to a boil, stirring regularly, and then reduce the heat to low to simmer. Simmer uncovered for a minute until the gravy thickens a bit.
To finish the dish, add the mushrooms and steak patties back into the pan, along with any juices on the plate. Spoon some gravy over the top of the steaks and mix the mushrooms into the sauce. Cover the pan partially with a lid set slightly askew, and leave the burner on low for five minutes until warmed through, stirring occasionally.