Bring large pot of salted water to boil for pasta. Stir in half a pound of short cut pasta and cook until al dente. Drain and set aside.
While pasta is cooking, bring butternut squash and chicken stock to boil in a separate pot. Cover and simmer 10-15 minutes or until squash is fork tender.
Using a potato masher, mash squash into a paste. DO NOT drain out the chicken stock. This will make the sauce.
Stir in garlic, salt, pepper, butter and 3/4 of the cheese and cooked pasta. Stir and add in more chicken stock to make sauce the consistency you desire, if needed. Sprinkle remaining cheese over top and serve immediately.