Tramezzino is a popular Italian triangular sandwich made with chewy, crustless white bread and various fillings such as mayonnaise, tuna, prosciutto, and cheese. It is believed that the first tramezzino was invented in 1925 at Caffè Mulassano in Turin.
It soon became incredibly popular, especially in Venice, where it's often enjoyed with a glass of Spritz. Today, there are numerous varieties of tramezzini, and they can be found in cafés throughout Italy, although pre-packed varieties that can be bought in supermarkets are also quite common.