They look like discs, or small green hockey puck type of buns.
I am looking for them in the So. NH No. MA area, but will travel as far as Boston. My neighbor just adopted a young girl from China and she informed me this was her favorite food, She and I cannot find them anywhere! I wanted to surprise her with some as a gift, so if you can tell me a place that sells them pre-made you would have made a young girl a tad less homesick.