01 -
In a large bowl, mix 2 tablespoons olive oil with minced onion and garlic, whisked egg, milk, mustard, ketchup, Worcestershire sauce, oregano, salt, pepper, and Italian breadcrumbs until well combined.
02 -
Add ground beef to the mixture and gently blend until evenly incorporated without overmixing.
03 -
Divide the meat mixture into four equal portions and shape each into oval patties approximately 2 cm thick.
04 -
Heat the remaining tablespoon of olive oil in a large skillet over medium-high heat. Sear patties for 3 to 4 minutes on each side until browned and cooked through. Remove and reserve.
05 -
In the same skillet, add diced onion and butter. Cook over medium heat until onions soften and turn golden, about 5 minutes.
06 -
Add sliced mushrooms to the skillet and cook until tender and moisture has evaporated, approximately 7 to 10 minutes.
07 -
Pour in beef broth and add bouillon cube, onion powder, garlic powder, and Worcestershire sauce. Bring to a simmer while scraping browned bits from the pan.
08 -
Whisk cold water with cornstarch to form a slurry. Stir slurry into simmering liquid and cook until gravy thickens, about 1 to 2 minutes.
09 -
Return patties to the skillet, nestling them into the gravy. Reduce heat to low, cover, and simmer for 10 to 15 minutes to meld flavors.
10 -
Serve patties hot with mushroom gravy spooned over. Recommended accompaniment includes mashed potatoes or rice.