Preheat the oven to 425 degrees F. Grease a 6-inch springform pan with olive oil. Wrap pan bottom with aluminum foil to avoid leaking in the oven.
Prepare the individual components of the pasta pie
Cook the pasta according to the directions on the packaging.
Mix ricotta with chopped parsley, mozzarella, egg, salt and pepper. Set aside
Peel the butternut squash, discard the seeds and cut it in cubes. Do the same with the onion and peel and squash the garlic.
Toss with olive oil, salt and pepper and roast in the oven until fork tender (approx. 20 minutes). Once tender, transfer into a blender, add vegetable stock, cream, salt, pepper and nutmeg until taste and thick. Reduce oven temperature to 375 degrees. F.
When pasta is cooked, drain and place tubes on kitchen towel, to avoid that the tubes stick together.
Assemble the pasta pie
Place the pasta in the form, as tight as possible.
Transfer the ricotta mixture into a Ziploc bag, cut a small corner off and pipe it in the pasta. Fill half way.
Pour butternut squash sauce on top of the pasta and 'work' the sauce into the pasta, as well as into the gaps between the pasta.
Top pasta with grated cheese (Mozzarella and Parmesan cheese).
Grease a sheet of aluminum foil with cooking spray and cover the springform pan. Place in oven and bake pasta pie for approx. 30 minutes.
Uncover and bake for another 15 minutes. The top will start to brown.
Allow the cheese to settle a little (approx. 10-15 minutes). Sprinkle with chopped parsley and remove the springform. Transfer pasta pie from bottom of springform pan into a serving dish.
Cut into wedges.
Notes
How much pasta do you need? That very much depends on the type of pasta you decide to use and the size of your pie dish. I used a 6-inch springform pan. Fill the springform pan with the dry pasta, this will help you to decide how much pasta you'll need.
To make the butternut squash sauce you can also use a blender or an immersion blender.