Meat:

1 ½ pounds 90% lean ground beef
½ cup dried breadcrumbs
1 large egg, beaten
1 tablespoon Worcestershire sauce
1 tablespoon soy sauce
3/8 cup tomato sauce
1 tablespoon dry mustard
1 teaspoon granulated garlic
1 teaspoon granulated onion
3 teaspoons dried oregano
Kosher salt and pepper
Finely chopped parsley, for serving
2 tablespoons olive oil

Gravy:

4 tablespoons unsalted butter
½ cup thinly sliced onion
8 ounces sliced mushrooms
2 cups beef broth
1 tablespoon tomato sauce
1 tablespoon soy sauce
1 tablespoon cornstarch or 2 tablespoons tapioca flour

    In a large bowl, mix the beef through the oregano together. Using your hands, form into fairly thin ovals, using some pressure to be sure the meat will hold together. Depending on the size of your ovals, can make 6-8 patties.
    Heat the olive oil in a large skillet over medium high heat. Place the patties in a single layer. Salt and pepper lightly. Cook 10-12 minutes, turning occasionally, until browned and cooked through.
    Once done, remove from pan to a warm plate and cover with foil.
    Wipe out the pan. Melt the butter then add onions and mushrooms. Sprinkle with salt and pepper. Cook for 5 minutes until softened. Whisk in tomato sauce, beef broth, and soy sauce.     Bring to a simmer. In a small jar, blend the cornstarch or tapioca flour with 2 tablespoons water.     Add the mixture to the pan and whisk until smooth. Let simmer a couple minutes until thickened.
    Add the meat back to the pan, and spoon gravy over the meat. Sprinkle with parsley before serving.