Gyudon is an extremely forgiving recipe for the beginner of Japanese cooking. In fact, should the cook at least stick to the ingredients and not add some of their own, I think it’s almost impossible to mess this dish up. It also cooks itself, with no need to stir, nudge, flip or watch, as long as it stays on low. The result, served over rice, is a savory and tender candied-meat extravaganza.