Moo goo gai pan is a chicken and mushroom stir-fried dish adapted for American tastes from the Cantonese dish, mah gu gai pin. In Cantonese, moo goo refers to the button mushrooms, gai to the chicken, and pan to the fact that the chicken is to be sliced. The vegetables and seasonings vary widely in this dish, but mushrooms and chicken are always used.
Other types of mushrooms can be substituted, but button mushrooms left whole are the traditional choice. Boneless chicken breast is used to make moo goo gai pan. Chinese cabbage and other Chinese vegetables are used in the original mah gu gai pin. Bamboo shoots, water chestnuts and snow peas may be used in some versions, while others just have broccoli along with the chicken and mushrooms.
Mah gu gai gin and some versions of moo goo gai pan contain oyster sauce. Oyster sauce is a dark sauce invented by Lee Kam Sheung, the founder of the Lee Kum Kee Company, in China's Guangdong Province in 1888. A sort of sweet and sour sauce called hoisin sauce is also sometimes used in these stir fries. Hoisin sauce is sometimes spicy and may be too strong for some Western tastes. Sesame oil may also flavor the dish, and peanut oil may be used for the stir frying.
Chinese rice wine may be used in recipes as well. It's produced from fermented glutinous rice, and the cooking varieties usually have less alcohol in them than those meant for drinking. Some Western chefs substitute cooking sherry for the rice wine, and pale dry sherry is considered a good substitute. Sake, the Japanese version of rice wine, does not make a good substituted because it is much sweeter than Chinese rice wine.