The present invention includes a device and a method of creating and using the device for maintaining the resonant temperature of a fried food product. The present invention is directed to a container cover comprised of two flat material pieces attached to one another to form an envelope-like structure with two or more sealed edges, an open end and a space between the material pieces and the creation of such a container. Additionally, the present invention is directed to a method of extending the duration of the resonant temperature of a fried food product by inserting a container of fried food products into the container cover of the present invention and attaching the container cover to the food container.