Preheat the oven to 375°F (190°C).

In a mixing bowl, combine ricotta cheese, chopped spinach, half of the mozzarella cheese, Parmesan cheese, egg, Italian seasoning, salt, and pepper. Mix well.

Spread a thin layer of marinara sauce on the bottom of a baking dish.

Lay a cooked lasagna noodle flat and spread a generous amount of the cheese mixture over it.

Roll the noodle tightly and place it seam-side down in the baking dish.

Repeat with remaining noodles and filling.

Pour the remaining marinara sauce over the rolled noodles and sprinkle with the remaining mozzarella cheese.

Cover the baking dish with aluminum foil and bake for 25 minutes.

Remove the foil and bake for an additional 5-10 minutes, or until the cheese is bubbly and golden.

Let cool for a few minutes before serving.