Abstract: A cooking apparatus in a form of a container includes an outer shell and an inner shell wherein a cavity is provided by coupling the edges of the outer and inner shells. The cavity is partially filled with a heat conductive medium, such as silicon oil. The cooking apparatus further includes an electric heating element installed under the container between the outer and inner shells. When energized, the heating element produces heat which in turn heats the silicon oil. The hot silicon oil heats the inner shell and thus cooks the food in the container. The outer shell of the container also has a pressure controlling member that is opened when a cavity pressure exceeds a predetermined value. The pressure controlling member comprises a spring housing securely affixed to the outer shell and defining a first through hole. The spring housing has a valve biased to open when a cavity pressure exceeds a predetermind value.

Abstract: The present invention relates to a cooking utensil having a double-layered structure which preserves heat efficiently as well as provides even heat distribution and to a method of fabricating such cooking utensil. The cooking utensil has a heat conduction medium charged between outer and inner shells forming a double-layered structure which is sealed by a curling machine without the use of a built-in safety valve in the wall of the cooking utensil.