Double boiled soup is not as its names suggests, a soup that is boiled twice, but the term refers to how the soup is cooked and the special pot that the soup is cooked in. Double boiled soup is actually a slow form of steaming and is used in Chinese cooking to prepare delicate foods such as bird’s nest or shark fin soup.
The food is placed in a special ceramic jar with two lids, the food is covered with water and the jar placed in a pot of water, rather like a bain marie.
In Cantonese, double steaming is called dun the meaning of which means to simmer or stew.This technique ensures there is no loss of liquid or moisture (its essences) from the food being cooked, hence it is often used with expensive ingredients like Chinese herbal medicines.
In this instance, a chicken thigh, along with some traditional Chinese herbal roots and dried fruits were placed in the jar. Above left, Dang shen (the dried roots of Codonopsis pilosula, a perennial species of flowering plant in the bellflower family), top right – dried goji berries, bottom left, star anise and bottom right, red dates.
This was left to simmer gently for 2-3 hours, always ensuring that the water in the main pan was kept topped up. The final results were eaten straight from the jar – absolutely delicious.
Cooking With Clay 