1. Preheat your oven to 375 F (190 C). Lightly grease a 9×13 inch baking dish with cooking spray or a little olive oil. If using regular lasagna noodles, boil them according to package directions until al dente, then drain and rinse with cold water to prevent sticking.

2. In a large skillet, heat the olive oil over medium heat. Add the chopped onion and cook until softened, about 5-7 minutes. Stir in the minced garlic and cook for another minute until fragrant. Add the chopped fresh spinach to the skillet and cook until it wilts down, about 2-3 minutes. Remove from heat and set aside.

3. In a large mixing bowl, combine the pumpkin puree, ricotta cheese, 1/2 cup grated Parmesan cheese, chopped fresh parsley, and the egg. Stir well until all ingredients are thoroughly combined and smooth. Fold in the cooked spinach and onion mixture. Season with salt and black pepper, mixing gently.

4. Spread about 1/2 cup of the alfredo sauce evenly over the bottom of the prepared baking dish. Arrange a single layer of lasagna noodles (usually 3-4 noodles, depending on your dish size) over the sauce, slightly overlapping if needed.

5. Spread half of the pumpkin ricotta filling evenly over the noodles. Drizzle about 1/3 of the remaining alfredo sauce over the filling, then sprinkle with about 1/2 cup of mozzarella cheese. Place another layer of lasagna noodles on top. Repeat this layering process: the remaining pumpkin ricotta filling, another 1/3 of the alfredo sauce, and another 1/2 cup of mozzarella cheese.

6. Place the final layer of lasagna noodles on top. Pour the remaining alfredo sauce over the noodles, spreading it to cover as much as possible. Sprinkle generously with the remaining mozzarella cheese and a little extra Parmesan cheese if desired.

7. Cover the baking dish loosely with aluminum foil (you might want to spray the underside of the foil with cooking spray to prevent cheese from sticking). Bake for 25 minutes. Remove the foil and continue baking for another 10-15 minutes, or until the cheese is bubbly and lightly golden brown, and the lasagna is heated through.

8. Once out of the oven, let the lasagna rest for 10 minutes before slicing and serving. This resting period allows the layers to set, making for cleaner slices and preventing the lasagna from falling apart.