The word 'mechoui' comes from Arabic and just means 'roasted'. The lamb is seasoned with simple ingredients - butter, salt, cumin, garlic and sometimes saffron - and then turned slowly over the fire for three or four hours. The cook keeps brushing it with butter so it stays juicy and the skin turns golden and crispy.
Different regions cook mechoui in different ways. In some parts of Algeria, the lamb is roasted on a spit over an open fire. In others, it is cooked underground - in a clay-lined pit with hot coals - which makes the meat soft and smoky. The underground way is sometimes called 'mechoui m'tamen' - 'buried mechoui'.
Mechoui is a sharing meal. The cooked lamb is placed on a giant platter in the middle of a big table or on a rug spread on the ground. Everyone sits around it and pulls off pieces of meat with their hands, usually dipping them in cumin and salt. There is no cutlery and no rush.
Mechoui is a marker of a special day. If you are invited to a wedding or family party in Algeria and you smell wood smoke as you walk up to the house, you can be almost sure there is a mechoui being cooked. People remember big celebrations by the mechoui that was served.