Couscous is not a grain in itself but a tiny, fluffy pasta — minuscule pellets of moistened durum-wheat semolina (Triticum durum) that are rolled, dried and then steamed until light and separate. It is the defining staple of North Africa, the bedrock of the Maghreb table from Morocco across Algeria and Tunisia to Libya, where a mound of pale-gold grains carries the broth, vegetables and meat of a tagine or a spiced stew. Steamed correctly it is dry, tender and granular, each pellet distinct rather than clumped, with a mild, faintly sweet, nutty taste that makes it a willing canvas for anything from saffron lamb to a lemon-and-herb salad. Most familiar in its fine form, it also comes as the larger, chewy pearls of Middle Eastern or Israeli couscous and the still-bigger Sardinian fregola.