Juicy, diner-style ground beef patties simmered in a silky mushroom-onion gravy. One-skillet comfort that’s weeknight-easy, meal-prep friendly, and perfect over mashed potatoes, rice, or noodles.
In a mixing bowl combine ground beef, panko, tomato sauce (or ketchup), egg, mustard, Worcestershire, oregano, pepper, and salt. Mix gently just until combined.
Shape into 4 oval patties about 3/4 inch thick; press a shallow dimple in the center of each to prevent puffing.
Heat 1 tablespoon oil in a large skillet over medium-high heat. Sear patties 3 minutes per side until well browned; transfer to a plate.
Add remaining 1 tablespoon oil to the same skillet. Sauté sliced onions and mushrooms over medium heat 5–7 minutes until softened and lightly browned.
Stir in onion powder, garlic powder, and Worcestershire. Pour in beef broth, scraping up browned bits from the pan. Bring to a simmer.
Whisk cornstarch with water to make a slurry; drizzle into the skillet while stirring. Simmer 2–3 minutes until the gravy thickens. Season to taste with salt and pepper.
Nestle the browned patties into the gravy, spooning sauce over the tops. Cover and simmer on low 10–12 minutes, until cooked through (internal temp 160°F).
Garnish with parsley if desired and serve hot over mashed potatoes, rice, or noodles with plenty of mushroom gravy.