Mix spinach, ricotta, 1/2 cup mozzarella, and egg.
Spray a casserole dish with cooking spray. Spead a think layer of pasta sauce on the bottom. Top with 3 lasagna noodles. Spread 1/2 the cheese mixture over the noodles, and top with 1/3 of the remaining pasta sauce. Layer 3 noodles on top. Spread with remaining cheese mixture and 1/3 pasta sauce. Layer last 3 noodles on top. Cover with reamining sauce and mozzarella. SPrinkle with parmesan.
Cover and bake 25 minutes in the preheated oven. COntinue baking uncovered 25 minutes, or until bubbly and lightly browned.