Gather all ingredients. Preheat the oven to 425 degrees F (220 degrees C).
Combine pasta, water, marinara sauce, meatballs, peppers, and salt in a 9x13-inch baking dish.
Cover tightly with aluminum foil and bake until pasta is al dente, 30 to 35 minutes.
Remove the foil and stir in 1 cup mozzarella cheese. Sprinkle with remaining 1 cup of mozzarella cheese and Parmesan cheese.
Bake, uncovered, until cheese is melted, 10 minutes more.
Serve garnished with fresh herbs, if desired.
