Preheat your oven to 350°F.
In a large mixing bowl, combine the ground beef, chopped onion, breadcrumbs, egg, garlic powder, salt, and black pepper. Mix until well combined.
Shape the mixture into oval patties, about 1 inch thick.
In a large skillet, heat the olive oil over medium heat. Brown the patties on both sides, about 3-4 minutes per side. Remove from skillet and set aside.
In the same skillet, add the beef broth and Worcestershire sauce, scraping up any browned bits from the bottom. Bring to a simmer.
In a greased 9x13 inch baking dish, layer the frozen mixed vegetables on the bottom. Place the browned patties on top of the vegetables.
Pour the beef broth mixture over the patties and vegetables.
Cover the baking dish with aluminum foil and bake for 30 minutes.
Remove the foil, sprinkle the shredded cheddar cheese on top, and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Let it cool for a few minutes before serving.
