Cha ca chien are fried fish pastties served as a snack, between Vietnamese Banh mi sandwiches, between lettuce leaves or in the udon noedle soup Banh canh. It takes some time to make them, the multi-applicability of the fish cakes is the reward for all the work.
They can also be freezed, which is especially easy with noodle soups or to pimp ready made noodle packages at any time. The fish of Cha ca chien can be minced roughly or finely to determine the desired structure of the fish cakes.
According to VietKings (Kyluc.vn)