The combination may sound boring, but it isn’t. I learned it from Lucy DiNapoli, whose mother came from Catania, Sicily. I cook the frittata in a heavy, well-seasoned 10-inch (25-cm) cast-iron frying pan, with a lid borrowed from another pot. It’s good hot or cool, or, leftover, in a sandwich made using a section of a long, narrow, crusty loaf.