the invention relates to a cooking device including a vessel for heating a cooking substance . the cooking substance is divided between a heating zone , a transition zone , and a cold zone . a first heating element is used to heat the cooking substance in the heating zone , and a transition zone heating device is used to heat the cooking substance in the transition zone . the transition zone heating device may be a pump for introducing a mixing medium into the cooking substance in the transition zone whereby the cooking substance in the heating zone mixes with the cooking substance in the transition zone . the mixing medium may be air , whereby the cooking substance in the heating zone is turbulently mixed with the cooking substance in the transition zone . the mixing medium also may be a portion of the cooking substance withdrawn by the pump from the transition zone and then reintroduced to the transition zone , thereby creating turbulence in the transition zone . the transition zone heating device may also be a second heating element . a method for operating a cooking device includes a vessel for heating a cooking substance . the cooking substance is divided between a heating zone , a transition zone , and a cold zone . the method comprises the steps of heating the cooking substance in the heating zone to a predetermined temperature and mixing the cooking substance in the transition zone with the cooking substance in the heating zone , thereby creating turbulence within the cooking substance in the transition zone . the turbulence is created by introducing air into the cook substance in the transition zone or by withdrawing a portion of the cooking substance from the transition zone and reintroducing the portion to the transition zone .