Step 1: Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish and spread 1/2 cup of your chosen sauce across the bottom.
Step 2: In a large mixing bowl, combine the pumpkin puree, ricotta cheese, sautéed spinach, half of the mozzarella, Parmesan, egg, garlic, nutmeg, sage, salt, and pepper. Stir until well combined.
Step 3: Lay out the cooked lasagna noodles on a clean surface or parchment paper. Pat them dry with a paper towel to ensure the pumpkin and spinach lasagna roll ups don't slip.
Step 4: Spread approximately 3 tablespoons of the pumpkin mixture onto each noodle, leaving a small gap at one end.
Step 5: Carefully roll each noodle up tightly and place it seam-side down in the prepared baking dish.
Step 6: Top the pumpkin and spinach lasagna roll ups with the remaining sauce and the rest of the mozzarella cheese.
Step 7: Cover the dish with foil and bake for 20 minutes. Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and slightly browned.
Step 8: Let the pumpkin and spinach lasagna roll ups rest for 5 minutes before serving to allow the filling to set.