Kipper

A kipper is a whole herring, a small, oily fish, that has been split in butterfly fashion from tail to head along the dorsal ridge, gutted, salted or pickled, and cold smoked over smouldering woodchips (typically oak).

In the United Kingdom, in Japan, and in some North American regions they are often eaten for breakfast. In the UK, kippers, along with other preserved fish such as the bloater and buckling, were also once commonly enjoyed as a high tea or supper treat; most popularly with inland and urban working-class populations before World War II.