In a large mixing bowl, combine ground beef, grated onion, garlic, salt and pepper, by hand. Add breadcrumb mixture and combine well. Form beef mixture into four oval-sized patties and refrigerate for 10 minutes.

Combine beef broth, Worcestershire and cornstarch; set aside.

Put a high-sided frying pan over medium high heat. Add 1-2 teaspoons oil and pan sear patties until browned, 2-3 minutes per side. Set patties aside on a clean plate.

In the same pan heat remaining oil and sauté diced onion and mushrooms until browned, stirring occasionally, about 4 minutes. Stir in tomato paste and cook for an additional minute. Stir in broth mixture and bring to a low boil. Reduce heat to a simmer.

Add patties back to gravy, cover and simmer an additional 5-8 minutes (or until patties reach an internal temperature of 160°F) flipping halfway through.