Cataplana

A cataplana is an item of cookware used to prepare Portuguese seafood dishes, popular on the country's Algarve region. According to The Oxford Companion to Food, the most famous dish made in a cataplana is amêijoas na cataplana (clams in cataplana).

The cataplana is traditionally made of copper and shaped like two clamshells hinged at one end and able to be sealed using a clamp on either side of the assembly. Cataplanas can also be made of aluminium.

...
Wikipedia