Banh khuc is a Vietnamese traditional cake. Bank khuc cake is mostly known in Northen Vietnam. It’s a rice ball made from glutinous rice, green bean, pork, spices and, most importantly, cudweed (khuc).
Cudweed grows during lunar January and February, when the drizzling rain lasts all day, and it can be found along the edges of rice fields. There are two kinds: nep and te. The latter is more flexible and fragrant and is preferred for making the cake.
First, the cudweed is washed, ground and then mixed with husked glutinous rice. Green beans, that are flayed and turned into paste after being cooked, are then added to the mixture. Finally, the cakes are sprinkled with grains of glutinous steamed rice.
As time goes by it is increasingly difficult to find cudweed as fields are eaten up by development. However, for now you can find banh khuc in Hanoi. However some bakers may not be using cudweed and may substitute it with cabbage or water morning glory.