In another saucepan, heat up 1/4 cup olive oil. Add the onion, butternut squash, salt, and black pepper. Cook for a few minutes. Then add the pasta and mix together. Add the water and allow the mixture to cook for 15 minutes or until the squash is fork tender. Cook's Note: To give the soup a creamier consistency, mash 1/2 the squash with the back of a fork.
While the butternut squash and pasta are cooking, shell the mussels and place them back into the saucepan. Transfer the mussel soup to the butternut squash soup. Mix together and add the Parmigiano cheese.