Peel the sweet potatoes and place them in a pot, covered with water. Boil them until tender, usually about 20 minutes after attaining the boil. Mash the sweet potatoes.
Sift the glutinous rice flour and the all-purpose flour together in a large mixing bowl. Blend
in the sugar and the mashed sweet potatoes. Knead the mixture until thoroughly combined, sprinkling in the hot water as you knead.
Knead the dough into small balls and then roll each ball into a flat round shape. Spoon a bit of red bean paste into each flattened round as a stuffing and knead the dough back into a round ball.
Coat the cookie balls with cold water, then cover thoroughly with the sesame seeds.
Over moderate heat warm a pan of oil that is deep enough to cover the cookies. Reduce the heat after the oil is warmed, and deep-fry the cookies on a low heat setting, until the balls have puffed up and are golden.