Abstract: A controllable temperature grid assembly (1) on which food can be cooked or defrosted is provided which includes an array of spaced tubular members (3) interconnected to form a generally planar grid (4) on which food to be cooked or defrosted can be placed for cooking or defrosting, with the hollow interiors of the members (3) also being interconnected to form a circulation flow path (5) for a heat exchange medium. The assembly (1) also includes heat exchange means (6) in fluid flow communication with the heat exchange medium circulation flow path for extracting heat from or supplying heat to the heat exchange medium. A thermostat is provided in the heat exchange medium for controlling the temperature to which the heat exchange medium is heated or cooled being recirculation through the tubular members (3).