Preheat your oven to 375°F (190°C).
In a large baking dish, combine the frozen meatballs, uncooked pasta, marinara sauce, Italian seasoning, garlic powder, black pepper, and water. Stir until well mixed.
Cover the baking dish tightly with aluminum foil and bake for 30 minutes.
Remove the foil and stir the mixture. Sprinkle the shredded mozzarella and Parmesan cheese evenly over the top.
Return the dish to the oven, uncovered, and bake for an additional 15-20 minutes, or until the cheese is melted and bubbly.
Let the casserole cool for about 5 minutes before serving. Garnish with fresh basil if desired.