Preheat oven to 350F. Prepare a 9x13 pan with nonstick spray.
In a large pot of boiling salted water, cook the pasta al dente. Drain and set aside.
In a large skillet, brown the ground beef until no longer pink. Drain.
Add the onion, garlic, italian seasoning, salt, pepper, and red pepper flakes. Cook until onion is soft and the garlic is fragrant.
Add the crushed tomatoes and stir to combine.
Add the ground beef back in and stir to combine.
In a large bowl combine the ricotta cheese, half the mozzarella cheese, and the beaten egg.
Add in the pasta and stir to combine.
Spread the cheese and pasta mixture in the pan.
Top with the meat and tomato mixture.
Top with remaining mozzarella cheese.
Bake uncovered for 30 minutes or until bubbly and the cheese is melted.
Remove and let sit 5 minutes.
Garnish with parsley and serve warm.