Cut leek lengthwise, wash and cut into rings. Cut ham into strips
Cook the pasta in boiling salted water according to the instructions on the packet. Heat the oil in a pot. Sauté the leek for 3-4 minutes, then add the ham. After about 1 minute, deglaze with cream and simmer gently for about 3 minutes. Season the sauce with salt, pepper and a little nutmeg
Coarsely chop the walnuts. Drain the pasta. Mix noodles and sauce and serve. Sprinkle the walnuts over the pasta.