Combine squash, onion, garlic, olive oil and salt on a sheet pan and toss to coat. Roast in the oven 30 minutes or until squash is fork tender. Cool slightly.
Reduce oven temperature to 175° C .
Add roasted squash to the bowl of a food processor and add cream cheese and stock. Blend for 5 minutes or until smooth. Transfer to a bowl and stir in sage and pepper.
Grease lasagna pan. Assemble lasagna by covering bottom with a layer of noodles. Next spread with ⅓ of squash puree and sprinkle with ⅓ of mozzarella cheese. Repeat layering of noodles, squash and cheese two more times. Top with final layer of noodles, Mozzarella and sprinkle with Parmesan cheese.
Cover with foil and bake 40 minutes. Remove foil and bake 15 minutes more or until top is golden brown and bubbly. Let sit 10 minutes before slicing.
