Preheat the oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish.

Bring a large pot of salted water to a boil. Cook the ziti pasta 2 minutes shy of al dente according to the package directions. Drain and set aside.

Heat the olive oil in a large skillet or Dutch oven over medium-high heat. Add the diced onion and cook until softened, about 4 to 5 minutes.

Add the ground beef to the skillet. Cook, breaking it apart with a spoon, until fully browned and no pink remains. Drain any excess fat.

Stir in the minced garlic and cook for 1 minute until fragrant.

Pour in the crushed tomatoes and Italian seasoning. Bring the sauce to a simmer, lower the heat, and let it cook for 10 minutes. Season with salt and pepper to taste.

In a medium bowl, combine the ricotta cheese, 1 cup of mozzarella cheese, Parmesan cheese, and fresh chopped parsley.

Toss the cooked ziti pasta into the ground beef sauce, mixing until the pasta is fully coated.

Spread half of the pasta and meat sauce mixture into the prepared baking dish.

Dollop the ricotta cheese mixture evenly over the pasta layer.

Top with the remaining pasta and meat sauce, then sprinkle the remaining 2 cups of mozzarella cheese evenly over the top.

Cover the baking dish tightly with aluminum foil and bake for 20 minutes.

Remove the foil and bake for an additional 10 to 15 minutes, or until the cheese is melted, bubbly, and slightly golden on top.

Let the baked ziti rest for 10 minutes before serving. Garnish with additional fresh parsley if desired.