For the Salisbury Steaks:

• Sauté the Onion and Garlic: Put 2 tablespoons of vegetable oil in a pan and set it over medium-low heat. Put in the diced onion and cook for about 4 minutes, until the onion turns clear. After you add the chopped garlic, cook for another 40 to 60 seconds, until the garlic smells good. Give it a minute or two to cool down after taking it off the heat.
• Prepare the Steak Mixture: Mix the cooked onions, ground beef, Panko breadcrumbs, egg, tomato sauce, yellow mustard, Worcestershire sauce, dried oregano, black pepper, and salt in a big bowl. Mix slowly with your hands; don’t mix too much or the steaks will be tough.
• Form the Steaks: Shape the mixture into 4-5 oval steaks.
• Brown the Steaks: Set the pan on medium heat and add the last 2 tablespoons of oil. Cook the steaks one side at a time for about one minute until golden. Place the cooked steaks on a plate.

For the Mushroom Gravy:

Cook the Onion and Mushrooms: Put 1 tablespoon of oil in the same pan and heat it over medium-low heat. It will take about 5 minutes of cooking the onion until it turns brown. Slice the mushrooms and add them. Cook until they turn brown.

Add the Beef Broth and Seasonings: Put the steaks back in the pan and add the beef stock. To make it taste better, add salt, pepper, Worcestershire sauce, onion powder, and garlic powder. Bring to a boil, then put a lid on top and cook for 15 minutes.

Thicken the Gravy: Mix flour and water (or beef stock) in a small bowl. Slowly add this mixture to the pan while stirring all the time. Add 5 more minutes of cooking time, or until the gravy gets thicker and the steaks hit 160°F (71°C) inside.