It’s considered a fundamental part of the city’s food identity. In other areas of Italy, however, it’s looked on with something approaching horror, because the “lampredotto” part of the name means beef tripe, as in, cow’s stomach.
More precisely, the meat in the sandwich comes from the fourth part of the cow’s stomach, technically called the “abomasum”, or colloquially in English, “reed tripe.” This part of the cow yields thin, flat meat.
The meat is simmered in a seasoned broth with some tomato in it until tender, then cut up into small square slices and served on a large round crusty bun cut in half. The sandwich maker will ask you if you want it “wet”, and if you say “yes”, they first will dunk both inner cut surfaces of the bun lightly in the simmering broth, just enough to moisten them. They do it by spearing a half of the bun with a fork, and then just lightly dunking it so that the surface of the bun just barely touches the broth, so as not to get the outsides all gloopy. Some vendors might just do the top half.
The meat on the bun is sprinkled with salt and pepper, and optionally garnished with either a green sauce or a spicy sauce. The top half of bun is then put on, and the sandwich is wrapped in paper (usually brown) to take it away with you. The price (2006) is around 2.50 euros ($3.25 US) for just salt and pepper, 3.00 euros ($4.00 US) if you want the bun dipped in the broth, plus the green and / or hot sauce.
The green sauce (“salsa verde”) might be made from basil, garlic, and olive oil, but every vendor has his or her own variation, that even they vary from time to time. Nerbone’s sandwich stall in Florence makes its green sauce from parsley, carrots, celery, and olive oil
The sandwiches are sold at tripe stands called “banchini dei trippai”, that will also sell other dishes from other forms of tripe. They keep the tripe hot all day in simmering pots. You can easily find the tripe stands in the San Lorenzo market (aka “Mercato Centrale”.) One food stall there, Nerbone, has reputedly been making these sandwiches since at least 1872.
Other markets in Florence where the sandwiches are sold are San Ambrogio (aka Il Porcellino, the Straw Market), Piazza de’ Cimatori, Piazza Dante Alighieri, Via Masi Fineguerra, Piazza dei Nerli, and Piazza Porta Romana, near the market of Sant’Ambrogio, Some stalls, such as those in the San Lorenzo market, are permanent ones; others are in vans that are moved out at night.
Panino con il Lampredotto was originally a poor person’s and workman’s sandwich.
In the 1400s, there were already lunch places in buildings that sold the tripe. By the 1800s, the cooked tripe was sold from painted wooden carts, pushed by hand and later, attached to bicycle mechanisms to pedal them about.
“Lampredotto” is derived from the Italian word for lamprey eels, “lampreda”, for the resemblance that the tripe was thought to have to cooked lamprey eel.