Cook the spaghetti in salted water until just al dente, set aside approx. 250 ml of the cooking water. Drain the spaghetti.
Crush the peppercorns using a mortar and pestle or the back of a knife, toast for approx. 2 mins. in a frying pan without oil. Add the spaghetti and approx. 100 ml of cooking water, cook the spaghetti, stirring occasionally. Combine the remaining cooking water with the cheese in a bowl, add to the spaghetti, mix until the cheese has melted.