Directions

1. Sift together 2 cups of cake flour and 2/3 cup of confectioners' sugar in a mixing bowl. Cut in the butter with a knife or pastry blender until the mixture resembles coarse crumbs. Stir 1/2 cup of water into the flour mixture until dough is formed. Cover and refrigerate for 20 minutes. Meanwhile, sift together 2 cups of cake flour with 2 tablespoons of confectioners' sugar in a small bowl. Knead in 1/2 cup shortening until dough is formed. Cover and refrigerate for 20 minutes.
2. Boil the candied waxgourd in 1/2 cup of water until candy is nearly tender. Drain and place in a blender. Blend waxgourd to a paste. Sift sweet rice flour and superfine sugar together in a bowl, then mix in the sesame seeds. Stir in 1/4 cup shortening and waxgourd paste. Gradually stir in 2/3 cup of water, mixing until dough forms.
3. Preheat an oven to 400 degrees F (200 degrees C). Line 2 baking sheets with parchment paper.
4. Divide each dough mixture into 25 equal portions. Take one portion of the the butter dough and roll out in the shape of a circle. Wrap one portion of the shortening dough with the butter dough in the shape of a ball, then roll the combined ball into an oval shape. Roll the dough up, lengthwise, into a tube shape then roll out once more into a long strip. Roll the dough up lengthwise again, pressing the ends down to secure. Shape the dough into a circle and place the sweet rice flour dough into the center. Wrap the outer dough around the filling creating a ball. Flatten the pastry into a circle and place seam side down on the prepared baking sheet. Repeat with the remaining portions. Prick holes on the top of each pastry using a fork. Brush each pastry with egg yolk.
5. Bake in the preheated oven until golden brown, about 20 minutes. Cool in the pans for 10 minutes before removing to cool completely on a wire rack.