In a large skillet, cook ground beef until crumbled and no longer pink. Drain fat. Stir in spaghetti sauce and tomato sauce. Set aside.
Combine cottage cheese, egg and parsley. Set aside.
Spray a 6-qt Slow Cooker with cooking spray. Spread 1 cup of sauce in bottom of slow cooker.
Top sauce with 4 lasagna noodles, breaking to fit. Spread 1/3 of cottage cheese mixture of on top of noodles. Top with 1/4 of mozzarella slices. Top mozzarella with 1/3 of remaining sauce. Sprinkle 1/3 of parmesan cheese on top of sauce.
Repeat layers two more times. - noodles, cottage cheese, mozzarella, sauce and parmesan. Top lasagna with remaining mozzarella slices.
Cover slow cooker and cook on LOW for 4 hours. Serves 6.