1. In a large bowl, combine the ground beef, breadcrumbs, Worcestershire sauce, egg, garlic powder, onion powder, salt, and pepper. Mix until just combined to avoid overworking the meat.
2. Shape the mixture into four equal patties, pressing gently to form them. Remember, as my abuela said, “Treat the meat with care, and it will take care of you.”
3. Heat olive oil in a large skillet over medium heat. Add the patties and cook until browned on both sides, about 4 minutes per side. Remove the patties and set them aside.
4. In the same skillet, add the mushrooms and onions. Sauté until they are softened and golden, about 5 minutes.
5. Sprinkle the flour over the mushrooms and onions, stirring to coat. Cook for an additional 1-2 minutes to remove the raw flour taste.
6. Slowly add the beef broth, stirring constantly to prevent lumps. Add the tomato paste and Dijon mustard, stirring until well combined.
7. Bring the mixture to a simmer, then return the patties to the skillet. Cover and cook for an additional 10-15 minutes, allowing the flavors to meld and the gravy to thicken.
8. Garnish with chopped parsley before serving for a fresh, vibrant touch.

This step-by-step process is designed to guide you with ease, just as my grandmother guided me with her stories and techniques, passing down culinary wisdom one pot at a time.