Preheat the oven to 400°F (200°C). In a mixing bowl, combine ground beef, bread crumbs, egg, garlic powder, onion powder, salt, and black pepper. Mix until just combined.

Form the mixture into meatballs, about 1 inch in diameter, and place them on a baking sheet.

Bake in the preheated oven for 20 minutes or until cooked through.

In a skillet, melt butter over medium heat. Stir in flour and cook for 1 minute until golden.

Gradually whisk in beef broth, Worcestershire sauce, garlic powder, onion powder, and black pepper. Bring to a simmer and cook until thickened, about 5 minutes.

Add the cooked meatballs to the gravy and stir to coat.

In a pot, cover cubed potatoes with water and add salt. Bring to a boil and cook until tender, about 15 minutes.

Drain the potatoes and return them to the pot. Add warm milk and butter, then mash until smooth. Season with salt and pepper to taste.

Serve the meatballs over a generous scoop of mashed potatoes, drizzled with gravy.