1. 1. In a large bowl, combine the ground beef, breadcrumbs, egg, Parmesan, garlic, onion, parsley, salt, pepper, onion powder, and garlic powder. Mix until just combined and roll into meatballs.

2. 2. Heat olive oil in a large skillet and brown the meatballs on all sides. Set aside.

3. 3. In the same skillet, melt butter and sauté mushrooms until browned.

4. 4. Sprinkle in flour and cook for 1-2 minutes. Gradually whisk in beef broth to prevent lumps.

5. 5. Add Worcestershire sauce and thyme; let simmer until thickened. Stir in heavy cream and season with salt and pepper.

6. 6. Boil diced potatoes in salted water until fork-tender. Drain and mash with milk and butter until creamy. Season with salt and pepper.

7. 7. Return meatballs to the skillet, nestling them in gravy. Simmer for about 10 minutes to cook through and meld flavors.