Preheat your oven to 350°F and grease your 9×13-inch baking dish.

If using frozen meatballs, heat them according to package instructions. For homemade, mix ground meat, breadcrumbs, egg, garlic powder, onion powder, and Italian herbs until well combined. Roll into bite-sized balls and bake for about 20 minutes until fully cooked.

Boil peeled and cut potatoes in salted water until fork-tender, around 15 minutes. After draining, mash them with butter, milk, and seasonings until creamy and smooth.

In a saucepan, heat the brown gravy over medium-low heat until warmed through, stirring occasionally.

Arrange your cooked meatballs in an even layer in the greased baking dish. Drizzle warm brown gravy generously over the meatballs.

Spread the creamy mashed potatoes evenly over the meatballs.

Sprinkle shredded mozzarella cheese over the mashed potatoes.

Bake in your preheated oven for 25-30 minutes, or until the cheese is melted and the edges are lightly browned. Let it cool for a few minutes before serving.