In the video, a person is seen cutting a purple onion into thin slices. The onion is placed on a wooden cutting board, and the person uses a knife to make precise cuts. The onion is already partially sliced, and the person continues to cut it into even thinner slices. The knife is sharp, and the person's hand is steady as they make each cut. The purple onion contrasts with the brown color of the wooden cutting board, making the slicing process visually appealing.