The best of the best (po boy) is made at Parkway Bakery & Tavern, a wood-frame building overlooking Bayou St. John. It comes tightly wrapped in a tube of butcher paper that already is mottled through with gravy splotches when you pick it up at the kitchen window. Unwrap it and behold a length of fresh, brawny bread loaded with beef so falling-apart tender that it seems not to have been sliced but rather hand-pulled, like fine barbecued pork, into myriad slivers, nuggets and dainty clumps. It is difficult to discern where the meat ends and gravy begins because there is so much gravy saturating the meat and so many carving-board scraps, known as debris (say DAY-bree), in the gravy.