Combine spinach, ricotta, Parmesan cheese, egg, garlic, Italian seasoning, salt and pepper in a medium size bowl.
Pour one cup of marinara sauce onto the bottom of a 9x13 baking dish.
Place a piece of waxed paper on the counter and lay out cooked lasagna noodles. Make sure the noodles are dry, and pat them with a paper towel if needed.
Take ricotta mixture and spread evenly over the noodles.
Carefully roll and place them seam side down onto your baking dish.
Repeat with all remaining noodles.
Ladle sauce over the noodle rolls in baking dish and top each one with 1 tablespoon of mozzarella cheese.
Cover baking dish tightly with aluminum foil and bake for 40 minutes or until cheese melts.