Boil up plenty of salted water for the pasta. Clean, wash and cut the leek into rings. Cut bacon into thin strips. Heat oil in a pan. Fry the bacon thoroughly. Add leek and steam. Season with salt and pepper.
Cook the pasta in boiling salted water according to the instructions on the packet until al dente. Wash parsley, shake dry, chop finely. Grate the parmesan finely.
Drain the pasta and fold into the bacon mixture. Serve sprinkled with parmesan and parsley.