Thaw spinach. In large mixing bowl, combine spinach, ricotta, parmesan, cream cheese and egg. In 13 x 9-inches baking pan, spread about 1 cup sauce. Then alternate layers of lasagna, cheese mixture, mozzarella, and sauce (usually makes 2-3 layers). Be sure to layer noodles to edges so whole surface is covered. Bake at 350 degrees F for 50 minutes (2 layers) or 1 hr (3 layers) then remove and let sit for 10 minutes.