Cook the pasta. Preheat the oven to 375°F. Lightly grease a 9×13-inch baking dish. Bring a large pot of well-salted water to a boil. Cook the ziti until just shy of al dente (about 1–2 minutes less than package directions). Drain and set aside.

Build the sauce base. Heat the olive oil in a large skillet over medium heat. Add the onion and cook for 5–6 minutes, until soft and translucent. Add the garlic and cook for 30 seconds, just until fragrant. Stir in the salt, black pepper, Italian seasoning, and red pepper flakes (if using).

Pour in the marinara sauce and simmer for 5–7 minutes to let the flavors meld. Remove from heat.

Make the ricotta mixture. In a large bowl, mix together the ricotta, egg (if using), ½ of the Parmesan cheese, and half of the mozzarella. Season lightly with salt and pepper.

Assemble the baked ziti. Toss the cooked pasta with the marinara sauce until evenly coated. Spread half of the pasta into the dish, dollop half of the ricotta mixture over the top, and gently swirl it in. Repeat with the remaining pasta and ricotta mixture. Sprinkle the remaining mozzarella and parmesan evenly over the top.

Bake + rest. Cover loosely with foil and bake for 20 minutes. Remove the foil and bake for another 10–15 minutes, until bubbly and lightly golden on top. If you want it a little darker, you can broil it for a few minutes (just watch it closely!). Let the baked ziti rest for 10 minutes before serving. Garnish with fresh basil or parsley, if desired.

Storage Instructions – Store leftovers in an airtight container in the refrigerator for up to 4 days.

Reheat in the microwave or cover with foil and warm in a 350°F oven until heated through.

To freeze, wrap tightly and store for up to 3 months. (more info on freezing up in the blog post)