An animal carcass cooking and roasting assembly and method of use in an oven, the assembly including a base tray, a liquid container mounted on and connected to the tray in a rack in a spaced apart upright position, the container arranged to receive a substantial amount of heat by conduction from the tray by the use of a tray and container connecting thermal via, the container arranged to fit within an open end of the carcass and wherein the opposite end of the carcass is tightly plugged or closed to form an isostatic chamber to contain liquid evaporated from the container within the carcass during the cooking process.