The tongue, cheeks, and maw were stage one of treating codfish after it was caught; this process was called ‘scaling the codfish’. These parts were consumed in order to use every part of the codfish, particularly in the case of the poorer classes. This snack is normally served with cooked cod, particularly in the Beira Litoral area.
Fish consumption in Portugal is associated with religious motivations (according to José Manuel Sobral and Patrícia Rodrigues in the article O fiel amigo: o bacalhau e a identidade portuguesa) and probably also with the fact that it is easy to access given the size of the Portuguese coast.
In the Portuguese countryside it was hard to access fish from the Ocean in the past so people resorted more to freshwater fish or codfish. Codfish was easy to preserve when salted and its entire body was usable: from tongue and cheeks (in brine), fish maw – dried fish swim bladder –, to the liver, a healthy oil source as well as small child trauma connected to it being compulsively ingested.
Let the cod tongues soak for approximately 12 hours. Cook them without seasoning them.
Remove excess liquid and dip them in flour and whisked eggs. Fry them in very hot oil. Remove excess liquid and serve with the following sauce: chop the onion, parsley, and boiled egg very well, then mix with olive oil, vinegar, salt, and pepper.
Guedes, F. (2001). As 100 maneiras de cozinhar Bacalhau e outros peixes. Publicações Dom Quixote
Sobral, J. M.; Rodrigues, P. (2013) O "fiel amigo": o bacalhau e a identidade portuguesa. Etnográfica 17 (3), p.619-649.