It’s a round Sicilian loaf of bread with sesame seeds on top. At least that is what it was until 1906 when the Muffuletta Sandwich was invented at the Central Grocery (which is still open) on Decatur St. in New Orleans. They cut the loaf horizontally and filled it with a marinated olive salad, Salami, Ham, Mortadella, with Provolone and Mozzarella.