Bring salted water to the boil in a large saucepan.
At the same time, bone the chicken and cut it into pieces.
Clean the chard, slice and put it in the saucepan, leaving it to boil for a couple of minutes.
In the meantime, heat a non-stick frying pan. Grease it with some butter and add a drizzle of oil. Dust the chicken with flour and cook it in a pan, cooking it well on the outside but leaving it soft on the inside. Halfway through cooking, season the chicken with grated lemon zest.
Heat another non-stick frying pan with a drizzle of oil and a clove of garlic. Cut the tomatoes in half and sauté them in the pan, pressing them lightly. Drain the chard and add it to the pan together with a little salt.
Cut two slices of bread and brown them a little on the griddle. Cut the Prosciutto di Modena PDO into thin slices.
Assemble the sandwich: lay the tomatoes and the chard on half of the bread. Cut the chicken into thin strips and add it to the bread. Finally, add the Prosciutto di Modena PDO. Top with the second slice of bread, previously soaked in the pan with what gravy is left after you cooked the chicken.
