In a big bowl, combine ground beef with bread crumbs, chopped onion, egg, Worcestershire sauce, and garlic powder. Season with salt and pepper.

Shape the mixture into oval patties, about ½ inch thick. You should get around 4 to 6 patties.

Heat olive oil in a large skillet over medium heat. Add the patties and cook without moving them for about 4-5 minutes until browned. Flip and cook for another 4-5 minutes on the other side. Remove from skillet and set aside.

If using mushrooms, add them to the same skillet and sauté for about 3-4 minutes until tender.

Pour in the beef broth and scrape any sticky bits from the pan. If you prefer a thicker gravy, mix cornstarch with a little water before adding it to the broth. Stir until it thickens, then return the patties to the skillet.

Spoon the gravy over the patties and let them soak up the flavor.

Boil salted water in a large pot. Add peeled and cubed potatoes and cook until tender, around 15-20 minutes.

In a small saucepan, melt butter over medium heat and sauté minced garlic until golden and fragrant. Add heavy cream and stir.

Drain the potatoes and return them to the pot. Pour the creamy garlic mixture over the potatoes and mash until smooth. Season with salt and pepper to taste.

Serve a generous amount of mashed potatoes on one side of the plate. Place a Salisbury steak on top and ladle gravy over everything.