In our "a stick and a pan" edition of "what it is?" both guessees guessed cotton candy, which is certainly what it looked like. But not so. Here's the sign above the booth to help you out:
The pricing is very interesting. To eat one cookie, you must first take five baths. No hints on how he verifies this requirement.
Now if you're wondering exactly how he makes his cookies, take a look at this picture. First he pours batter into the metal container. It has many small holes in the bottom, which he uses to pour the batter into the pan. Finally he uses a stick to roll it up, thus making the cookie.
We didn't actually try one of the cookies, so I'm can't make any statements on the strength of his claim to make the best cookies.