Halfway through cooking, cook the spaghetti pasta in a large pot of boiling salted water until aldente. Transfer the pasta to the sauce, reserving some of the cooking liquid. Whip the remaining extra virgin olive oil and salt to taste. Add a little of the pasta cooking liquid if needed. Laddle the spaghetti on a plate, finish with a few grinds of pepper and orange zest. Serve and pass Grated parmesan cheese if desired.