Preheat your oven to 375°F (190°C).
In a 9x13 oven-safe baking dish, combine the spaghetti noodles, marinara sauce, chicken broth or water, oregano, minced garlic, and chopped onion. Make sure the spaghetti is fully submerged in the liquid.
Stir the ingredients together, ensuring that the noodles are evenly distributed and coated with the sauce and broth.
Place it in the preheated oven. Bake for 45 minutes, stirring halfway through to ensure even cooking.
After 45 minutes, remove the foil and sprinkle the shredded mozzarella cheese evenly over the top of the spaghetti. Return the dish to the oven, uncovered, and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Let the dish cool for a few minutes before serving. Enjoy with a sprinkle of parmesan!
