This dessert  is called "khao niew ping". It is basically sticky rice with a mystery contents grilled in banana leaves over a charcoal fire. You need to ask what it contains unless you like to be surprised. To ask, just say "sai a-rai". The choices are: banana, taro, shredded coconut or mung beans. Not too bad if you are not expecting much. These cost 6 baht each.