Natalie and I learned how to make this at a Sur La Table cooking class. It was served with spinach linguini alongside crispy prosciutto.
Roast walnuts for 10 mins at 375°. Add half the nuts to the cream, sage, garlic, S&P, cheese in a food processor. Make it smooth.
Put the sauce into a large bowl. Add pasta and toss until coated. Add pasta water to thin the sauce.
Serve with hand-crushed walnuts on top along with more cheese and the parsley.