Often two or three porchetta trucks may be parked at the same spot. Invariably, there will be a longer line at one of them, for obvious reasons. When you get to the window, you’re asked if you want the porchetta sliced from the fat end or the lean—and, of course, the fat end is the best. You always have to buy more than you need, because it’s hard to get home without eating some along the way, especially the crispy skin. Porchetta is delicious warm, but perhaps even better room temperature or cold.