Start by boiling a large pot of water for the noodles and cook noodles according to the package instruction. Toss the noodles with a little olive oil so that the noodles do not stick.

Pre-heat the oven to 350 degrees.

In a large saucepan or large skillet over medium-high heat add 1 tablespoon olive oil and the diced onions, saute for 2 minutes and then add the Italian seasoning, red pepper, and garlic, saute for additional 1 minute. Add the marinara sauce and spinach, stir until everything is incorporated.

In a 13by9 in baking dish add a quarter of the spinach pasta sauce to the bottom of the dish, spread over the bottom of the dish. Sprinkle the sauce with 1 cup Mozzarella and half of the ricotta. I did this by dropping 8-10 dollops of ricotta evenly throughout the baking dish. Then pour the noodles into the dish, then add the rest of the ricotta mixture, add again spread evenly as dollops. Then spread the rest of the sauce over the noodles and ricotta. Top with the parmesan cheese and remaining mozzarella.

Bake for 20 minutes until lightly brown on top.

If taking the ziti from out the refrigerator, it might need 30-35 minutes to get hot and bubbly. I would also suggest covering the baking dish with aluminum foil and removing for the last 5 minutes of baking so that it can get slightly brown on top.