The Sandwich Cassoulet folds the heaviest casserole in the French repertoire into a loaf. Cassoulet, the dish of Toulouse and Carcassonne, is white beans cooked long and slow with duck or goose confit and garlic sausage until the beans are soft to the point of collapse and the whole thing binds into a thick, fat-rich mass. The sandwich is the leftover form of that pot: a split crusted loaf packed with the beans, a few shreds of confit and sausage broken through them, often a swipe of strong mustard against the bread. It eats less like a sandwich and more like a stationary picnic.
The logic is that the cassoulet is already a complete thing and the bread is only a way to hold it. The beans bring their own fat, their own salt from the sausage, their own depth from the confit, so nothing needs adding except maybe the mustard for an acid edge against all that richness. The constraint is weight and softness: cassoulet has no structure of its own, the beans yielding the moment they are pressed, so the sandwich stays small and the bread does all the structural work. The loaf has to be dense and well-crusted to carry a heavy, collapsing filling without going to paste. The window is narrow. Slightly warm, the beans are loose and the fat is soft and the sandwich is at its point; cold, the fat sets firm and the loaf turns leaden; hot, it falls apart in the hand. It eats best warm, never hot, never properly cold, and not long after it is built.
Variations stay on the Languedoc shelf. A version weighted toward the garlic sausage gives a coarser, meatier bite against the soft beans; one pushing the duck confit further makes the whole sandwich richer and asks the mustard to work harder; the plainest is beans and their own fat alone, the casserole standing as the entire filling. Each holds the white-bean-and-confit mass as the fixed point and changes only the balance within it. The Sandwich Cassoulet belongs with the casserole-into-bread tradition the catalog groups under Plat-en-Sandwich, the regional dishes that began as a plate of food and were later folded into a loaf. Its specific contribution is sheer weight as a design constraint: a sandwich asking dense bread to hold a dish that has no structure of its own.