Preheat oven to 425°F. Spray/grease a deep 9x13-inch baking dish.
In a large bowl, mix together the uncooked pasta, marinara sauce, milk, broth, garlic powder, onion powder, Italian seasoning, salt, pepper, meatballs, and parsley.
Add mixture to the prepared baking dish, and press the pasta into the liquid.
Cover tightly with aluminum foil and bake for 50-60 minutes.
Carefully remove the foil and stir the casserole. Check to see if the pasta is done, it should be firm but almost fully cooked. If it’s not done, re-cover and bake for 5-10 more minutes.
Uncover and sprinkle the parmesan cheese evenly over the top. Then sprinkle the mozzarella cheese over the top and bake uncovered for 5–10 minutes, until the cheese has melted and the casserole is bubbly.
Let the dish rest for 10 minutes before serving.
Optional: Place under the broiler for a few minutes before serving if you want the cheese browned.