Sesame Balls (Jian Dui)

Soak prunes in 1½ cups hot water in a medium bowl until very soft, about 20 minutes. Drain, reserving ¼ cup soaking liquid.

Transfer prunes to a blender. Add sugar and lemon juice and purée, adding reserved soaking liquid to loosen if needed, until smooth, thick, and jam-like. Transfer filling to a small bowl. Cover and chill at least 1 hour.

Do Ahead: Filling can be made 1 day ahead. Keep chilled.

Mix 2 Tbsp. mochiko and 1 Tbsp. room-temperature water in a small bowl. Knead dough with your hands until smooth, then form into a ball.

Transfer dough to a small saucepan of boiling water (it should be submerged) and cook until it looks glossy, about 3 minutes. Transfer to an ice bath and let cool; drain.

Mix sugar, baking powder, and 1¼ cups plus 2 Tbsp. mochiko in a large bowl. Add cooked dough, breaking up with 1 hand while gradually stirring in ⅓ cup room-temperature water. Transfer dough to a clean work surface and knead, adding more flour to prevent sticking, until a smooth dough forms (it should feel soft and supple), about 5 minutes.

Fill a clean small bowl with room-temperature water. Place sesame seeds in another small bowl.

Shape dough into balls that are about 1½" in diameter (you should have 10). Working one at a time, flatten into a pancake and make a divot in the center. Place ½ tsp. prune filling in divot and wrap dough over. Roll into a smooth ball, pinching together any holes.

Holding with one of your hands, dip ball into bowl of water, then use your other dry hand to dip ball into bowl with sesame seeds and toss to coat evenly.

Pour oil into a large saucepan fitted with thermometer to come halfway up the sides. Heat over medium-high until thermometer registers 350°. Working in batches, fry sesame balls, turning often, until deep golden brown, about 6 minutes per batch. Transfer to a wire rack set over paper towels and let drain. Let cool 5 minutes before serving.