In North Alabama, and at Big Bob Gibson’s in particular, the barbecue pork shoulder tends to be cooked low and slow, over hickory, until the poor pig gives up the ghost. But it’s the chicken – spatchcocked, grilled, and “baptized,” as the grandson of the restaurant’s namesake puts it, with the white barbecue sauce Gibson himself invented back in the 1920s – that steals the spotlight here. In the intervening years, that white sauce has become standard across the region, but there’s nothing like the original.