Preheat oven to 375 F.
For this filling, you will need to have pre-cooked butternut squash puree.
Using food processor, combine 2 cups of butternut squash puree with Ricotta cheese, milk, salt and nutmeg.
Add more milk if needed (to make the butternut squash filling very creamy).
Mix very well, taste and add more salt, if needed.
Combine spinach, Ricotta cheese, mozzarella, garlic, salt and pepper. Mix, taste, and add more salt and pepper, if needed.
Cooking lasagna noodles:
Bring a very large pot of water to boil, and cook lasagna noodles according to package instructions. Rinse in cold water, drain. Using knife, trim noodles to fit your baking dish (if necessary).
Prepare a baking dish – I used a casserole dish 11 inches x 8.5 inches x 3 inches deep. Grease the lasagna dish lightly with olive oil spray.
Spread 1/3 of butternut squash filling on the bottom of the dish.
Sprinkle lightly with mozzarella cheese.
Top with cooked lasagna noodles without overlapping (I used 3 noodles).
Spread half of spinach filling over the noodles. Top lightly with Mozzarella cheese. Top with cooked noodles.
Spread another layer (1/3) of butternut squash mixture, then sprinkle lightly with Mozzarella cheese. Top with cooked noodles.
Spread the remaining half of spinach filling over the noodles. Top lightly with Mozzarella cheese. Top with the final layer of cooked noodles.
Spread a generous amount of butternut squash filling (the remaining 1/3) over this final layer of noodles, sprinkle with grated Parmesan and remaining mozzarella cheese (about 1/2 cup of mozzarella). Generously sprinkle the cheese with Italian seasoning, paprika, basil.
Cover the baking dish with foil and bake for 30 min. Remove foil and bake additional 10 minutes.