The most typical panino in Firenze: panino con il Lampredotto
Lampredotto sellers can be found everywhere in town.
A peasant dish made from the fourth and final stomach of a cow, boiled in water with tomatoes, onion,celery, and parsley (as any other bollito), served with salt and pepper or salsa verde (parsley sauce)
In the rest of Italy Trippa (‘tripe’ the stomach of a cow) is a common dish in several regions.
Trippa alla Romana, with tomatoes, pecorino, and herbs
(See also “I miss Italian foods foreigners cannot handle – 1 ‘ 2″