A cazuela is traditionally used as the serving dish for gambas al ajillo in Spanish tapas cuisine.
A cazuela is a shallow earthenware cooking or serving vessel. For gambas al ajillo, shrimp, garlic, olive oil, and chili are heated in the vessel and brought directly to the table, where the dish may still be sizzling.
The earthenware helps retain heat and suits the tapa’s presentation. Diners commonly eat the shrimp with bread, using it to soak up the strongly flavored oil.
A cazuela should not be confused with a paella pan or a metal frying pan. The word can refer broadly to Spanish earthenware cookware, while in this context it describes the small vessel used for cooking and serving the tapa.