Bring a large pot of salted water to a boil. Add the 12 oz of ziti pasta and cook according to package instructions until al dente. Drain and set aside. Reserve about a cup of pasta water in case you want to loosen the sauce later.
Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes. Stir in the minced garlic and cook for another 30 seconds until fragrant. Add 1 lb of ground beef, breaking it apart with a spoon, and cook until browned and cooked through. Season with salt and pepper.
Once the beef is browned, pour in the 28 oz can of crushed tomatoes. Add 2 teaspoons dried oregano and 1 teaspoon dried basil. Stir well and let the sauce simmer gently for 15-20 minutes until it thickens slightly. Taste and adjust seasoning as needed.
In a medium mixing bowl, combine 2 cups ricotta cheese, 1 egg, and half of the grated Parmesan cheese. Mix until smooth and creamy. This mixture will add richness and help bind the layers together.
Preheat your oven to 375°F (190°C). In the 9x13-inch baking dish, spread a thin layer of meat sauce on the bottom. Add half of the cooked ziti pasta over the sauce. Dollop and spread half of the ricotta mixture over the pasta. Sprinkle with 1 cup of shredded mozzarella.
Repeat the layers with the remaining pasta, ricotta mixture, meat sauce, and top everything with the remaining mozzarella and Parmesan cheese.
Cover the baking dish with foil and bake for 25 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese on top is melted, bubbly, and golden brown. Let it rest for 5 minutes before serving.