Step 1: Cook the Pasta : Bring a large pot of salted water to a boil.Cook ziti until just al dente (about 1–2 minutes less than package instructions). Drain and toss lightly with olive oil to prevent sticking. Set aside.

Step 2: Make the Sauce : In a large skillet over medium heat, heat olive oil.Add Italian sausage and cook, breaking it up with a spoon, until browned (about 5–6 minutes). Add diced onion and cook until softened, 3–4 minutes.Stir in garlic and cook for 30 seconds until fragrant.Add marinara sauce, oregano, basil, salt, and pepper. Simmer on low for 5 minutes.

Step 3: Prepare the Cheese : Mixture In a medium bowl, combine ricotta, egg, Parmesan cheese, and 1 cup mozzarella.Mix until well blended.

Step 4: Assemble the Ziti : Preheat oven to 375°F (190°C). In a greased 9x13-inch baking dish:Spread 1/3 of the sauce mixture on the bottom.Add half of the pasta. Dropspoonfuls of ricotta mixture over pasta and spread gently.Add another 1/3 of sauce, then remaining pasta, then remaining sauce.Sprinkle the remaining 1 cup mozzarella evenly over the top.

Step 5: Bake : Cover the dish loosely with foil (to prevent cheese from burning). Bake for 20 minutes covered, then uncover and bake another 10–15 minutes until bubbly and golden.Let rest for 5–10 minutes before serving.