Heat the oven to 350°F. Grease a 9x13-inch baking dish.
Cook the egg noodles in salted water until just tender. Drain.
Meanwhile, cook the ground beef and onion in a large skillet until the beef is browned and no pink remains. Drain the fat. Stir in the pasta sauce.
In a bowl, stir together the cottage cheese, egg, Parmesan and Italian seasoning.
Spread half the noodles in the dish. Top with the cottage cheese mixture, half the meat sauce and 1 cup mozzarella. Add the rest of the noodles, the rest of the sauce and the last cup of mozzarella.
Bake uncovered 25 minutes, until bubbly and the cheese is melted. Let stand 10 minutes before cutting.
Notes
Refrigerate leftovers within 2 hours, up to 4 days. Reheat to 165°F.