Prepare Meatball Mixture: In a large mixing bowl, combine ground beef, breadcrumbs, egg, and chopped onions. Add garlic powder, salt, and black pepper. Gently mix until combined.

Shape Meatballs: Form the mixture into 1-inch meatballs and place them on a plate.

Cook Meatballs: Heat a skillet over medium heat, add oil, and cook the meatballs for 10-15 minutes until browned and cooked through.

Make Gravy: In the same skillet, add beef broth and let it simmer. Stir in a thickener to achieve desired gravy consistency.

Prepare Mashed Potatoes: Boil chopped potatoes for 15-20 minutes until tender. Drain and return to pot.

Mash Potatoes: Add butter and milk to the potatoes, mash until creamy, and season with salt and pepper.

Combine and Serve: Return meatballs to the skillet with gravy, heat through, and serve over mashed potatoes.