1. Prepare and Shape Hamburger Steak Patties:
- In a large bowl, gently combine the ground beef, breadcrumbs, beaten egg, Worcestershire sauce, garlic powder, onion powder, salt, and pepper.
- Mix with your hands just until the ingredients are evenly combined. Be careful not to overmix, as this can make the patties tough.
- Divide the mixture into 4 equal portions and gently shape each into an oval patty, about 3/4 to 1 inch thick.
2. Sear the Patties:
- Heat 1 tablespoon of the butter or oil in a large skillet over medium-high heat.
- Carefully place the patties in the hot skillet (work in batches if necessary to avoid overcrowding).
- Sear for 3–4 minutes per side, until nicely browned on both surfaces. The patties do not need to be fully cooked through at this stage.
- Remove the seared patties from the skillet and set aside on a plate.
3. Cook the Onions:
- Reduce the heat under the skillet to medium. If there isn’t much fat left in the pan, add the remaining 1 tablespoon of butter or oil.
- Add the thinly sliced yellow onion to the skillet.
- Cook, stirring occasionally, for 10–12 minutes, until the onions are very soft, translucent, and golden brown. Allow them to caramelize slightly for deeper flavor if desired, adjusting heat as needed to prevent burning.
4. Make the Gravy:
- Sprinkle the 2 tablespoons of all-purpose flour evenly over the softened onions in the skillet.
- Stir constantly for about 1 minute, coating the onions and cooking out the raw flour taste.
- Gradually and slowly pour in the beef broth while stirring or whisking constantly. Continue stirring/whisking vigorously to prevent lumps from forming as the gravy base comes together.
- Bring the mixture to a simmer, stirring, until it begins to thicken slightly. Taste and adjust salt and pepper if needed.
5. Simmer Patties in Gravy:
- Carefully return the seared hamburger steak patties (and any accumulated juices from the plate) back into the skillet with the onion gravy.
- Spoon some of the gravy and onions over the tops of the patties.
- Reduce the heat to low, cover the skillet with a lid, and let the patties simmer gently in the gravy for 15–20 minutes, or until they are cooked through and tender.
6. Serve:
- Serve the Hamburger Steaks hot, generously smothered with the rich onion gravy.
- Garnish with fresh chopped parsley, if desired. These are classically served over mashed potatoes, rice, or egg noodles.