It might seem odd to list slaw as a Tarheel specialty. Slaw is everywhere and, really, how good could it be? In the barbecue parlors at the center of the state, it can be the star attraction. Mixed with house-made sauce and God-know-what other ingredients that chefs tend to keep secret (pimento cheese? curry powder? hot peppers? tart pickles?), it can serve as a salad, a dip, or the secret element of meat loaf. But it reaches fullest glory when piled atop a mound of smoke-cooked pork.