Begin by preheating your oven to 350 degrees Fahrenheit (175 degrees Celsius). While it’s heating, spray a 9x13-inch baking dish with cooking spray to prevent sticking. This is crucial for a neat serving later on!

Fill a large pot with lightly salted water and bring it to a rolling boil over high heat. Toss in the ziti and stir right away to prevent sticking. Cook the pasta uncovered for about 8 minutes, ensuring it’s al dente – firm but still cooked through. Once done, drain the pasta well and set aside.

While your pasta is boiling, grab a large skillet and heat it over medium heat. Add the Italian sausage, breaking it up with a spatula as it cooks. Stir occasionally for about 10 minutes until it's browned and fully cooked. Afterward, drain any excess fat and place the cooked sausage aside.

In a large mixing bowl, combine the ricotta cheese, chopped onion, egg, minced garlic, oregano, salt, and pepper. Stir well until everything is fully incorporated and looks creamy. This mixture is going to add such rich, delightful layers to your baked ziti.

Add the cooked ziti and browned sausage to the ricotta mixture. Pour in half of one jar of your spaghetti sauce and mix until everything is evenly coated. The sauce should hug every piece of pasta, giving it a delicious flavor.

Grab your prepared baking dish and pour about one-third of the remaining spaghetti sauce at the bottom. This layer helps keep the pasta from drying out. Now, add half of your ziti and sausage mixture. Spoon on half of the remaining sauce, then sprinkle half of the shredded cheese over that. It’s like building a cheesy ziti lasagna!

Repeat the layering with the remaining pasta mixture, topping it with the rest of the sauce and cheese. If you're feeling adventurous, sprinkle the grated Parmesan cheese on top along with the optional basil for that burst of flavor.

Cover the dish tightly with aluminum foil and let it bake in your preheated oven for about 20 minutes. After that, remove the foil and return it to the oven for an additional 5 to 10 minutes, until the cheese is melted and bubbly.