Southern California has In-N-Out Burger, Wisconsin has Culver’s, Biloxi has Burger-Burger. Okay, so this spot in a converted bungalow renowned for its hamburger po-boys (in business since the 1940’s and referring to itself as a “mini-museum of Biloxi nostalgia”) hasn’t been franchised, but with a few tweaks, it certainly could be. A special mustard sauce and additional secret sauce go into the classic sandwich. Save room for pie. Lunch only.