Preheat oven to 350°F. Spray a 13x9-inch baking dish with cooking spray. Set aside.
Cook ziti in salted water per the package directions until al dente. Drain well and set aside.
In a large pot or Dutch oven cook olive oil and onion for 2 minutes over medium high or just until softened and translucent.
Meanwhile, in a bowl season ground beef and Italian sausage with 2 Tbsp Parmesan cheese, Italian seasoning, salt, black pepper, granulated garlic, onion powder and crushed red pepper flakes.
Add meat mixture to the onion in pot. Cook over medium-high heat until no pink remains. Drain excess fat from the pan.
Add marinara sauce and ziti to pot, Stir with a large spoon until evenly coated.
Assemble: Pour 1/2 into prepared dish. Dollop with 1/2 of ricotta cheese. Sprinkle ricotta with 1 1/2 cups shredded mozzarella cheese. Repeat with remaining ziti, dollops of ricotta and drizzle with 1 cup marinara sauce.
Sprinkle the top with reserved 1 1/2 cups mozzarella cheese and 2 Tbsp Parmesan cheese.
Transfer to the oven and bake for 40-45 or until bubbly and golden brown.
Serve immediately. (Garnish with fresh parsley or basil, if desired.)