The Gsaa is a wide, shallow platter with slightly sloped sides, usually made out of pottery or wood, used for preparing couscous and mixing and kneading dough. In the north and around Fès, the platters tend to be terra-cotta. The best are made from the wood of the walnut tree (in French, bois de noyer) from the Ourika Valley on the western slope of the High Atlas, and sometimes from oak (bois de chêne). Standard sizes range from 16 to 20 in/40.5 to 51 cm in diameter, though larger ones are not uncommon. Crafted from a single piece of wood, they are heavy, around 1B⁄c in/4 cm thick, and very sturdy. It’s usually recommended to place a folded kitchen towel underneath the gsâa while working to keep it stable; dampen the towel to keep the gsâa from slipping when vigorously kneading bread.