In the video, a person is cooking onions in a pan. The onions are being stirred and tossed around in the pan. The person then adds ketchup to the pan and continues to stir the onions. The onions are cooked until they are caramelized and have a rich, golden brown color. The ketchup adds a sweet and tangy flavor to the onions, making them even more delicious. The person stirs the onions and ketchup together until they are well combined and the ketchup is evenly distributed throughout the onions. The video ends with the onions and ketchup simmering in the pan, creating a mouth-watering aroma.