Abstract: The invention relates to food preparation methods. The technical result of implementing the invention consists in preserving the quality of the food, saving energy used for heating, and reducing the time required for preparation of food. The technical result is achieved by heating of entire volume of water or food inside a container, and subsequently dividing the water or food into a portion to be heated further and a remaining part, where the division occurs after a certain period of time after heating has started. The water or food may be in the liquid, semi-liquid or solid state when placed inside the container.