The panino con falafel is an immigrant sandwich reading on Italian bread, and what defines it is the fried chickpea ball meeting a loaf it was not built for. Falafel is soaked chickpeas, raw, ground with herbs, garlic, and spice, shaped into balls or patties and deep-fried so the outside is a hard craggy shell and the inside stays green and crumbly. On the Italian street it has stepped onto the same counter as the salume roll, filled not into pita but into a rosetta, a length of ciabatta, or a piadina, which changes how the sandwich has to be held together.
The craft is managing a dry, crumbly filling so it does not fall out of a bread with no pocket. The falafel must be fried hot enough to set a firm crust fast, because an underfried ball collapses to paste under the weight of the bread and a sauce. Crushed slightly into the loaf, the balls knit into a layer rather than rolling loose. The dressing does the work the bread shape will not: a tahini or yoghurt sauce binds the crumble and waterproofs the crust from inside, and pickled vegetables or a sharp salad cut the density of the fry. The bread is usually plain and fairly soft so it yields against a firm filling rather than fighting it, and it is filled and eaten promptly, before the sauce softens the crumb or the falafel loses its crispness sitting in the heat.
The variations follow the city street: the version wrapped in a piadina the Romagnola way, the one set in a soft sesame roll closer to its Levantine home, the build that adds grilled vegetables or hummus alongside. Each is a different bread adapting the same fried chickpea, and each deserves its own article rather than being crowded in here.