Preheat oven to 400°F.
Combine everything: Add the marinara, water, heavy cream, Italian seasoning, onion powder, sugar, salt, and dry pasta directly to a 9×13 baking dish. Add your protein if using and stir well to combine.
Cover tightly Cover the dish tightly with foil (a double layer is best to trap steam).
Bake Bake for 30–35 minutes, or until the pasta is tender.
Stir and top Remove foil, stir everything together, then top with Parmesan and mozzarella.
Broil Broil for 3–5 minutes, until the cheese is melted and lightly golden.
Let it rest Let sit for a few minutes before serving so the sauce can thicken.