The Kentucky burgoo sandwich is the rare case where the filling is a stew that was never meant to be picked up. Burgoo is a thick, long-cooked Kentucky stew of several meats and vegetables simmered down until it is dense rather than soupy, and the sandwich is what happens when that stew is reduced far enough and spooned onto bread instead of into a bowl. The defining decision is the reduction. A loose stew runs straight through bread and off the plate; a burgoo cooked down until it holds its shape on a spoon becomes a filling, and the sandwich exists only at that thickness.
The craft is entirely in the pot and the carrier, because there is no assembly to speak of. Burgoo is built from whatever meat is on hand, often mutton, pork, beef, or game, cooked with corn, beans, potatoes, and tomato over hours until the meat falls apart and the vegetables collapse into the body of the stew and thicken it. To carry it on bread it is reduced harder than it would be for a bowl, until the liquid has cooked into the solids and the mass is spoonable but not running. It is laid on a soft, sturdy slice or a plain bun whose only job is to soak the edge that does run and give the hands something to hold while a hot, heavy, soft filling does all the work. There is no crunch and no acid built into the sandwich; it is one warm, dense, savory texture by design, the stew's own depth standing in for any contrast a constructed sandwich would add.
The variations are mostly the cook's hand and the region's larder rather than codified builds, since burgoo has no single recipe and changes with whatever the pot is fed. Served open under a ladle of the same stew it edges toward a hot-plate sandwich eaten with a fork; piled tighter and capped it reads closer to a sloppy, slow-cooked sandwich in hand. It belongs to the dense long tail of regional American specialties that travel badly and stay home on purpose, and those relatives deserve their own articles rather than being crowded in here.