In a large mixing bowl, combine 2 pounds of ground beef, ½ cup of breadcrumbs, 1 beaten egg, 1 medium finely diced onion, 2 teaspoons of salt, and 1 teaspoon of black pepper. Mix gently until just combined to keep the hamburger steaks tender. Shape the mixture into 6-8 oval patties and let them rest while you preheat your oven to 350°F.

Heat an oven-safe skillet over medium-high heat. Once hot, add the hamburger patties in a single layer and cook for 3-4 minutes per side until golden brown. Set aside on a plate while you prepare the gravy.

In the same skillet, reduce the heat to medium and add 3 tablespoons of butter. Once melted, sauté 1 large sliced onion until softened, about 5 minutes. Sprinkle 3 tablespoons of all-purpose flour over the onions, stirring for about 2 minutes until lightly golden. Gradually whisk in 2 cups of beef broth and 1 cup of heavy cream until smooth and thickened.

Nestle the browned hamburger patties into the creamy gravy, ensuring they are submerged. Cover and bake at 350°F for 45 minutes. Uncover and bake for an additional 15 minutes.

Once baked, let the dish rest for about 10 minutes to allow flavors to meld and the sauce to set. Serve alongside creamy mashed potatoes or buttered egg noodles.