In a pot of salted boiling water, cook the pasta until al dente. Drain and oil lightly, setting 125 ml (1/2 cup) of cooking water aside.
In the same pot, melt the butter. Add the cream and 55 g (3/4 cup) Parmesan cheese and heat thoroughly. Add the pasta and toss to coat. Season with salt and pepper. Add a little cooking water, if needed, for a creamy sauce.
Divide the pasta among four plates. Garnish with the remaining Parmesan cheese and parsley. Serve immediately.