Step 1: Cook the Pasta

1. Preheat oven to 375°F (190°C).
2. Boil a large pot of salted water and cook ziti pasta until al dente. Drain and set aside.

Step 2: Prepare the Meat Sauce

1. Heat olive oil in a large skillet over medium heat. Add ground beef or sausage and cook until browned.
2. Add diced onion, cooking until softened (about 3 minutes). Stir in minced garlic and cook for 1 more minute.
3. Pour in crushed tomatoes, tomato sauce, and tomato paste. Stir well.
4. Season with basil, oregano, red pepper flakes (if using), salt, and pepper. Simmer for 10-15 minutes, stirring occasionally.

Step 3: Make the Ricotta Mixture

1. In a bowl, mix ricotta cheese, egg, and chopped parsley until combined.

Step 4: Assemble the Baked Ziti

1. Spread a thin layer of meat sauce in a large baking dish.
2. Layer half of the cooked ziti over the sauce.
3. Spread half of the ricotta mixture over the pasta.
4. Sprinkle 1 cup mozzarella and 1/4 cup Parmesan cheese on top.
5. Repeat layers with remaining pasta, ricotta, and meat sauce.
6. Top with remaining mozzarella and Parmesan cheese.

Step 5: Bake

1. Cover dish with foil and bake for 20 minutes.
2. Remove foil and bake for an additional 10-15 minutes until cheese is golden and bubbly.
3. Let rest for 10 minutes before serving.