Bring a large pot of salted water to a boil. Cook the ziti until al dente, following the package instructions. Drain and set aside.

In a large skillet, heat olive oil over medium heat. Add the diced onion and cook until soft and translucent, about 3-4 minutes. Stir in the minced garlic and cook for another minute. Add the ground Italian sausage (or beef) and cook until browned, breaking it up as it cooks. Drain excess fat if needed.

Pour in the marinara sauce, dried oregano, dried basil, crushed red pepper flakes, salt, and black pepper. Stir well and let the sauce simmer for 10 minutes to develop deep, rich flavors.

In a bowl, combine the ricotta cheese, egg, grated Parmesan, and a pinch of salt and pepper. Mix until smooth and creamy.

Preheat the oven to 375°F (190°C). In a large baking dish, spread a thin layer of the meat sauce on the bottom. Layer half of the cooked ziti, followed by half of the ricotta mixture, half of the remaining meat sauce, and half of the shredded mozzarella. Repeat the layers with the remaining ingredients.

Cover the dish with foil and bake for 20 minutes. Then, remove the foil and bake for another 10-15 minutes until the cheese is bubbly and golden brown on top.

Let the baked ziti rest for a few minutes before serving. Garnish with freshly chopped basil and extra Parmesan, then enjoy!