Preheat the oven to 350 degrees. Spray an 8-inch springform pan or a 9 inch deep-dish pie plate with cooking spray.
Cook the pasta in a large pot of salted, boiling water for 6 to 7 minutes or until almost al dente. (The pasta will continue cooking in the oven.). Drain and set aside.
In a large skillet, brown the ground beef over medium heat until no longer pink, approximately 4 to 5 minutes. Transfer to a bowl using a slotted spoon and discard the fat from the pan (leave a couple teaspoons for sauteing the onion).
Return the pan to the heat and cook the onion until softened, approximately 3 to 4 minutes. Add the garlic to the pan and cook for 1 minute. Stir in the Italian seasoning and onion powder. Remove from the heat and set aside.
In a large bowl, whisk together the sauce, ricotta cheese, parsley and eggs. Stir in the onion mixture.
Toss the pasta and beef with the sauce mixture to combine. Stir in 1/2 cup parmesan and 1/2 cup mozzarella. Transfer the spaghetti mixture to the prepared pan. Sprinkle the remaining cheese over the top.
Bake until the cheese is melted and bubbling, approximately 25 to 30 minutes. Remove from the oven and allow to rest for 5 minutes before cutting and serving.