These fish-shaped treats are Portuguese desserts that originated in convents. The cakes consist of thin dough and a filling that is made with a combination of egg yolks, ground almonds, sugar, and cinnamon. They are finished off by dipping the ends in chocolate, while the whole cakes are occasionally dusted with cinnamon sugar.

As the name implies, the origin of these unusually-shaped desserts is associated with Trancoso, and they are believed to have been invented at the Santa Clara convent.