The sformato di patate or gattò, the Italianization of the French ''gateau'', is a savory potato ‘cake’ made of mashed potatoes enriched with eggs, butter, grated cheese with a filling of cheese, ham or other cold cuts and vegetables.
Typically served warm, but not piping hot, it can be either a one-dish meal (piatto unico), if accompanied with salad, or an antipasto, if served in thin slices.