Heat oven to 350°F. Spoon 1 cup beef sauce into baking dish. Arrange 4 lasagna noodles over sauce, breaking to fit if necessary. Spoon half of remaining sauce over noodles. Top with all of spinach. Evenly spoon half of cottage cheese mixture over spinach. Top with 1 1/2 cups of the mozzarella cheese. Repeat layers of noodles, beef sauce and cottage cheese mixture. Cover tightly with foil.