Cook the Pasta:
Preheat your oven to 375°F (190°C).
Bring a large pot of salted water to a boil. Add the ziti pasta and cook until al dente, according to the package instructions. Drain and set aside.
Prepare the Meat Sauce:
In a large skillet, heat the olive oil over medium heat. Add the diced onion and cook until translucent, about 5 minutes.
Add the minced garlic and cook for another 1-2 minutes until fragrant.
Add the ground beef to the skillet, breaking it up with a wooden spoon. Cook until browned and cooked through, about 8-10 minutes. Drain any excess fat.
Stir in the marinara sauce, diced tomatoes, dried oregano, dried basil, salt, and pepper. Let the mixture simmer for 10 minutes, allowing the flavors to meld together.
Assemble the Ziti:
In a large mixing bowl, combine the cooked ziti pasta with half of the meat sauce. Mix until the pasta is evenly coated.
Spread half of the pasta mixture into a large baking dish.
Sprinkle half of the shredded mozzarella cheese and half of the grated Parmesan cheese over the pasta.
Pour the remaining meat sauce over the cheese layer.
Top with the remaining pasta mixture, spreading it evenly.
Finish by sprinkling the remaining mozzarella cheese and Parmesan cheese on top.
Bake the Ziti:
Cover the baking dish with aluminum foil and bake in the preheated oven for 20 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly, and the edges are slightly browned.
Serve:
Remove the baked ziti from the oven and let it cool for a few minutes.
Garnish with chopped fresh parsley if desired.
Serve hot and enjoy!