A method of popping popcorn in a microwave includes operating an energy source to provide energy to a cooking chamber and detecting, by a microphone sensor, sound waves in the cooking chamber and providing an output signal indicative of the detected sound waves to a control unit. The control unit can determine that the output signal is indicative of a popping sound generated by popcorn kernels popping and control the energy source to stop providing energy to the cooking chamber based on the detected popping sounds.