According to tradition, Cardinal Eugenio Pacelli asked a restaurant in the Vatican neighborhood to make him a more delicate version of “Spaghetti alla Carbonara.” So, the chef substituted fettuccine for the spaghetti, prosciutto for the guanciale (cured pork jowl) and Parmigiano Reggiano for the pecorino, and he also added a splash of cream. Buon appetito!