A buttermilk-inspired marinade gives a rich umami flavor to your fried chicken. | SIMON DALY Everyone knows fried chicken. It is a near-universal dish with interesting variations around the world. The frying itself is pretty much the same across various cultures, too — what’s different are the marinades used to flavor and soften the meat, and the dry coating applied before frying. In Japan, fried chicken, or karaage , tends to be marinated in a soy sauce base. In the American South tradition, the fowl is coated in buttermilk, a cultured milk that serves as a replacement for cream. The recipe below gives karaage a Southern fried twist by marinating it in umami-rich buttermilk.…