Couscous
Couscous, not actually a grain but a form of pasta, cooks quickly. Ideally, it is steamed over a spicy stew, from Stifado (page 336) to Chicken and Lentil Tagine (page 284), and certainly you can do that. But you will probably prepare it more frequently if you treat it somewhat like rice, as I do here. The couscous benefits from a short preliminary toasting, which brings out more flavor (otherwise, what you have is plain pasta); alternatively, turn it in butter as I do in the variation.