Preheat your oven to 375°F (190°C) and grease a 9x13 inch baking dish with butter or nonstick spray. Bring a large pot of salted water to boil and cook the ziti according to package instructions until al dente, about 8-10 minutes. Reserve 1/2 cup pasta water before draining, then set aside.

In a large skillet over medium heat, cook the ground beef and diced onion for 5-7 minutes, breaking up the meat with a wooden spoon until browned and the onion is translucent. Add the minced garlic and cook for one additional minute until fragrant.

Stir in the crushed tomatoes, Italian seasoning, salt, and pepper. Let the sauce simmer uncovered for 10 minutes, stirring occasionally, until it thickens slightly and turns a deeper red color with oil beginning to separate at the edges.

In a large bowl, combine the cooked ziti, meat sauce, and ricotta cheese. Mix thoroughly until every piece of pasta is well coated. If the mixture seems dry, add a splash of the reserved pasta water.

Spread half of the pasta mixture into the prepared baking dish. Top with 1 cup mozzarella cheese and 1/2 cup Parmesan cheese. Add the remaining pasta mixture and finish with the rest of the mozzarella and Parmesan.

Cover the baking dish tightly with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 15 minutes until the cheese is bubbly and golden brown around the edges. Let rest for 5 minutes before garnishing with fresh parsley and serving.