Often made with a heavy, cloying, canned commercial syrup and covered with sickening melted marshmallows, candied sweet potatoes have earned a bad reputation throughout the South. Today, however, cooks are learning to respect the dish more, and when candied sweet potatoes are prepared properly, there’s no more luscious addition to the holiday table—or, for that matter, to any formal or informal buffet. I knew one lady in Chattanooga, Tennessee, who always sprinkled a big handful of crushed