Knead the tofu and rice flour together, mashing the tofu well with your hands. Once the mixture forms a smooth dough, shape it into a log. Divide into 20 pieces and roll the pieces into small balls.* Cook the balls in boiling water: once they rise to the surface, cook for a further 2 minutes. Transfer the cooked rice balls to a bowl of cold water to cool them down quickly. Drain, then thread 4 balls onto a skewer. Char the surface of the balls on a wire grilling rack, either on the barbecue or over a gas ring. If you don’t have a grilling rack, you can char them on a high heat in a dry frying pan.
To make the syrup, place all the ingredients in a saucepan and bring to the boil, stirring constantly with a wooden spatula. Reduce the heat to low, and continue to stir and cook for another minute until the syrup becomes thick and clear. Roll the skewers in the syrup so the balls are well coated.