A method includes: obtaining temperature-related information which is related to temperatures at portions of a cooking container, using a processor; recognizing an edge of the cooking container disposed in a cooking device that cooks by heating, and identifying an overheated portion in the edge where a temperature exceeds a threshold value, based on the temperature-related information using the processor; and transmitting emission instruction information to a light emitter, and causing the light emitter to emit light to the identified overheated portion.