Ceviche de almejas is a variation of the traditional ceviche dish, using clams as the primary ingredient. Just like other ceviches, the clams are "cooked" using the acid from citrus juices, usually lime, which denatures the proteins. Fresh, raw clams are shucked, cleaned, and marinated in freshly squeezed citrus juice.
The acid in the juice "cooks" the clams, turning their flesh more opaque and firm, similar to the effect of heat cooking. Like other ceviche variants, ceviche de almejas is usually mixed with finely chopped onions, coriander, and spicy chili peppers, usually rocoto.