On a large work surface, lay out a towel and lay out cooked lasagna noodles onto it. Divide the spinach ricotta mixture among the noodles, and spread out evenly on each noodle. Roll each one and place seam side down in the baking dish.
Spread the rest of the sauce over the rolls and top with remaining ½ cup of mozzarella. Bake covered for 45 minutes, until hot and bubbly. Uncover for the last 5 minutes to be sure the cheese is melted.