Method
Preparation
Preheat the oven to 350°F (175°C).
In a large bowl, mix together the ground beef, chopped onion, breadcrumbs, egg, salt, and pepper until combined.
Form the mixture into evenly sized patties.
Cooking
In a large skillet over medium heat, brown the patties on both sides until they develop a nice crust, about 3–4 minutes per side.
Place the browned patties in a baking dish in a single layer.
In the same skillet, add the sliced mushrooms and sauté over medium heat until tender, about 5 minutes.
Pour the beef broth over the patties and mushrooms in the baking dish, making sure everything is evenly distributed.
Cover the baking dish with aluminum foil and bake for 30 minutes.
Remove the foil, sprinkle the shredded cheese on top of the patties, and bake for an additional 10 minutes or until the cheese is melted and bubbly.
Serving
Garnish with fresh parsley before serving, and serve hot with mashed potatoes, noodles, or a simple green vegetable.
Notes
Evenly sized patties ensure consistent cooking. Brown the patties well for extra flavor. Let the bake rest 5 minutes before serving to redistribute juices.