Start by preparing a thick soup with the Tuscan kale: slice the onion thinly, heat some extra-virgin olive oil in a saucepan and leave it to stew. Take the green part of the leaves of the Tuscan kale, slightly cutting the stem. Use a knife to cut the leaves into very small pieces and add them to the saucepan. Add the white beans and a glass of water. Season with salt and pepper and leave it to stew.
Cut two slices of bread and heat them on a griddle.
In the meantime, put a non-stick frying pan on a high heat. Add extra-virgin olive oil and a clove of garlic. Cut the beef into very thin slices and brown it gently only on one side. Once it is cooked, add salt to taste.
To assemble the sandwich: on one piece of bread, first lay the meat, then the vegetables and finally some slices of Prosciutto Toscano PDO (sliced by hand or by machine). Take the second slice of bread, use it to sop up what’s left in the pan where you cooked the beef, and then close your sandwich.