Cook lasagna noodles according to package directions. Drain, rinse, and set aside.
In a large skillet, over medium heat, brown the ground beef, and drain fat. Add onions and garlic and cook for 2-3 minutes, cooking until the onions begin to become transparent.
Stir in the marinara sauce, salt and pepper. Simmer over medium heat, stirring occassionally until the sauce thickens, approximately 5 minutes.
In a medium bowl, mix together 2 cups of mozzarella, 1/4 cup Parmesan cheese, ricotta cheese, and egg. Fold in chopped parsley.
Assemble: Spread 1 cup of meat sauce in the bottom of a 9x13 casserole dish. Top with 3 lasagna noodles, 1/3 of the cheese mixture, and 1 cup of meat sauce; repeat 2 times. Top with the remaining 3 noodles and meat sauce. Finally, top with the remaining mozzarella and Parmesan cheese.
Cover with foil and bake for 45 minutes. Remove foil and bake for an additional 15 minutes.
Remove from oven, allow to rest for at least 10 minutes before serving.
Notes
*The Nutritional Facts that have been calculated on this recipe are only estimates.