Any effort to produce a Cajun menu outside New Orleans produces the same kind of argument about authenticity that people have about barbecue and deli food. The Po’Boy Shop is obviously mindful of that. Their po’boys start with French bread from New Orleans’ Leidenheimer bakery — and they are all traditionally dressed with a spicy remoulade, lettuce, tomato, mayo, and pickles. Oysters, shrimp, catfish, grouper, sausage, muffaletta, and chicken tenderloins are among the close to 20 varieties available, including cheeseburger, vegan burger, and the notorious Debris, a sandwich made with roast beef slow-cooked so long it falls apart, producing fat “debris” used to make gravy, served with a horseradish sauce.