Preheat oven to 375 F. Cook lasagna noodles according to package directions, drain. In a medium bowl, combine ricotta cheese, egg, grated parmesan cheese, 1 cup shredded mozzarella cheese, and spinach.
Evenly spread a thin layer of marinara sauce in a large baking dish. Spread the ricotta spinach mixture on each lasagna noodle. Roll up tightly and place into the baking dish.
Cover with the marinara sauce and sprinkle with the remaining shredded mozzarella cheese. Cover with foil and bake for 30 minutes. Uncover and bake for another 5-10 minutes, until the cheese has melted.