In the video, a person is seen using a toothpick to check the doneness of a chocolate cake. The cake is inside a round, metal baking pan and is placed on a rack. The person inserts the toothpick into the center of the cake and waits for a few moments. After a while, the person pulls out the toothpick and checks if it comes out clean. The cake appears to be fully cooked as the toothpick comes out clean.