Heat your oven to 375°F (190°C) and lightly grease a 9x9-inch baking dish.
Evenly spread the mashed potatoes across the base of the prepared dish, seasoning with salt and pepper if you like.
Arrange the cooked meatballs evenly on top of the mashed potatoes.
Pour the brown gravy evenly over the layers to cover all the meatballs and potatoes.
Scatter the shredded cheese on the top layer.
Place the dish in the oven and bake uncovered for about 20 to 25 minutes, until everything is hot and the cheese has melted and is bubbling.
Sprinkle chopped parsley or green onions on top for a fresh finish, then serve warm and enjoy a comforting family meal.