The Buffalo chicken finger sub is defined by a format choice that changes the whole sandwich: the fillet is not one piece but a row of fried chicken fingers laid down the length of a sub roll. Strips instead of a single cutlet is the engineering, not a shortcut. Each finger has its own all-around crust, so a long roll packed with them has more fried surface and more sauce-gripping edge than a flat fillet could offer, and the gaps between strips become channels that hold Buffalo sauce and blue cheese instead of letting them run off the side. This is a wing plate rebuilt as a sandwich, and the row-of-fingers structure is why it earns a name distinct from a single-fillet build.
The craft is keeping a wet emulsion from defeating a crisp coating across a long sandwich. The fingers are brined and fried hot for a craggy shell sturdy enough to be tossed in liquid, then tossed, not drizzled, in the Buffalo sauce, cayenne pepper sauce whisked with melted butter until the fat carries the heat onto every surface and gives it enough body to cling. The defense against the resulting sogginess is the rest of the build: a sturdy sub roll with enough crust to hold a heavy, greasy, wet load without folding, a thick stripe of blue cheese dressing that doubles as a moisture barrier between sauce and bread, and crisp lettuce and a celery-style crunch carried straight off the wing platter. The cool, the fat, and the crunch are the structural counterweights that keep the hot, vinegary fillet reading as balanced rather than punishing. It is assembled and served fast, before the sauce works through the crust and the roll.
The variations are small dials on a settled idea: ranch in place of blue cheese for the milder reading, the heat moved by the cayenne-to-butter ratio, lettuce and tomato in or out. It sits in the American fried chicken sandwich family and is a close regional cousin of the bun-format Buffalo chicken sandwich and the Nashville hot build, separate answers to carrying aggressive heat on fried chicken. Those deserve their own articles rather than being crowded in here.