Start by bringing a large pot of salted water to a boil. Add the lasagna noodles and cook according to package instructions until al dente—usually about 8 to 10 minutes. Gently drain and lay the noodles flat on a clean kitchen towel to prevent sticking.
In a large bowl, combine the pumpkin puree, chopped spinach, ricotta cheese, minced garlic, egg, dried oregano, salt, black pepper, and nutmeg. Stir everything together until smooth and evenly mixed.
Spread a thin layer of the pumpkin-spinach mixture evenly over each lasagna noodle, leaving a small border on the edges. Next, sprinkle some shredded mozzarella and grated Parmesan cheese on top of the filling. Carefully roll up each noodle from one end to the other.
Preheat your oven to 375°F (190°C). Spread half of the marinara sauce on the bottom of your baking dish. Place the lasagna roll-ups seam side down in a single layer. Pour the remaining marinara sauce over the top and sprinkle with any leftover mozzarella and Parmesan cheese. Cover the dish with foil and bake for 25 minutes. Remove the foil and bake for another 10 minutes, or until the cheese is bubbly and golden.
Allow the roll-ups to cool slightly before serving. They pair wonderfully with a crisp green salad or a warm bowl of Creamy Roasted Pumpkin Soup for a full meal experience.
