Century eggs
A delicacy throughout Asia, the century egg, also known as preserved egg, hundred-year egg and thousand-year egg, is made by preserving duck, chicken or quail eggs in a mixture of clay, ash, salt, quicklime, and rice hulls for several weeks to several months. Through this process, the yolk turns a dark green/grey in colour and develops a pungent flavour, due to the hydrogen sulfide and ammonia present. The white becomes a dark brown, translucent jelly with a salty flavour.