Fettuccine Al Prosciutto

SEPARATE FAT AND LEAN parts of prosciutto. Chop fat coarsely; cut lean into 1/2-inch squares. (If prosciutto has little or no fat, simply increase butter by 1 to 2 tablespoons.) Melt butter in a skillet. Add onion and prosciutto fat and saute 5 minutes. Add prosciutto squares and saute 2 to 3 minutes. Off heat, salt very lightly and pepper generously. With a slotted spoon, remove half the prosciutto and reserve. Boil the fettuccine in a large quantity of salted water 1-2 minutes, until al dente. Drain in a colander but not too thoroughly: leave them a little moist. Transfer fettuccine to a heated serving bowl. Toss with entire contents of saute pan. Add grated cheese and more freshly ground pepper, and toss again. Strew reserved prosciutto on top and serve at once.