Food products, for example, hamburger patties, are more rapidly cooked than with existing systems and with reduced shrinkage in a cooking appliance which has a number of parallel spaced heat transfer fins. An array of projecting cooking grills on which the hamburger patty is impaled are thermally connected to these fins. This appliance is introduced into a liquid heating medium so that heat is transferred through the fins and projecting grills to the interior of the hamburger patty. In this way cooking is accomplished in a relatively short period of time, and the amount of fat and meat juices that are melted or boiled away is reduced. An ejector fits between the projecting cooking grills to remove the food patty after the cooking is completed.