It's essentially leftovers turned into a sandwich — the same simmered bean stew served in a bowl at dinner gets ladled into a baguette the next morning.
Black-eyed peas are simmered down with tomato, onion and chili into a thick, spicy stew, then spooned into a halved baguette with mayonnaise and hot sauce. Dakar's baguette vendors and street-corner tables sell it as a filling, cheap breakfast eaten on the move.