The Socca Sandwich is the chickpea pancake of Nice put to work as something you fold and fill, eaten warm in the hand on the move. Socca itself is a thin batter of chickpea flour, water, and olive oil poured onto a wide pan, baked hot until the surface blisters and the edges crisp, and normally eaten plain off a paper square with cracked pepper. The sandwich is what happens when that round is treated as bread rather than a snack on its own: it is folded around or wrapped over a filling and carried off as street food. Because the batter is chickpea flour, the result is naturally gluten-free, which is the trait that sets it apart from every wheat-based sandwich in the catalog. The region recorded for it is Nice.
The craft is in how socca behaves when it has to act as a wrapper. It has no gluten, so it does not stretch or fold the way a wheat flatbread does; it is tender and a little crumbly, which means it is folded gently around a modest filling rather than rolled tight or overloaded. The contrast is the appeal: a crisp, faintly charred exterior from the hot pan against a soft, almost custardy interior, with the chickpea itself carrying a nutty, earthy weight that stands up to assertive fillings. The olive oil in the batter keeps it from drying as it sits, but only briefly, and the timing is unforgiving: socca is best within a few minutes of coming off the heat, while the edge still snaps and the inside is still soft, and it stiffens as it cools. The filling stays restrained because the round is fragile and a savory chickpea base does not need much help.
The variations stay inside the Niçois snack tradition rather than wandering out of it. The same chickpea round is most often eaten plain with pepper and no filling at all; the panisse, the fried chickpea stick from the same flour, is a close relative handled differently. The Socca Sandwich belongs with the southern bread snacks the catalog groups under Pissaladière & Niçois Bread Snacks, the Niçois tradition of intensely flavored things eaten by hand off a paper square between meals. Its particular contribution is a gluten-free chickpea round standing in for bread, fragile enough that the sandwich's whole job is not to overwhelm it.