Make the dough: Place the flour in a large bowl. Pour the boiling water over the flour and stir to mix it in. Add the cold water and stir together. Press the dough together into a ball and knead for a few minutes until the dough is smooth. Place the ball of dough in the bowl and cover with a damp towel. Let the dough rest for 30 minutes.

Prepare the filling: Chop the Chinese chives into ½-inch pieces and place in a bowl. Sprinkle the salt over the chives and mix to evenly distribute. Let sit for 15 minutes. Squeeze the liquid out of the chives. Discard the liquid and place the chives in a bowl with the ground pork, soy sauce, and sesame oil. Mix together.

Assemble the turnovers: Cut the dough in half and set one half under the damp towel. Roll the dough out into a 1.5-inch diameter log and cut into 12 equal pieces. Place all but one of the disks under the damp towel. On a lightly floured work surface, roll the disk out to about a 6-inch diameter and 1/16-inch thickness. Place 2-3 tablespoons of filling on half of the dough disk, flattening the filling to leave at least ½-inch margin at the rounded edges. Fold the dough over the filling to create a half-moon shape and push out any air pockets. Press the edges together to form a good seal and then crimp, pinch, or fold the edges however you like. Repeat for the remaining dough.

Alternative assembly: Instead of turnovers, my parents make these into a kind of filled pancake. Cut the dough in half and set one half under the damp towel. Roll the dough out into a 1.5-inch diameter log and cut it into 6 equal pieces. Place all but two of the disks under the damp towel. On a lightly floured work surface, roll both disks (one at a time) out to about a 7-inch diameter and 1/16-inch thickness. Place ⅓ to ½ cup of filling on one of the dough disks and spread to within ½-inch of the edge. Set the second disk on top of filling and match up the edges of the dough as best you can. Press out any air bubbles and then press the edges together with your fingers, making sure to seal the filling in. Take a medium-sized round plate and hold it so the base is facing you and the service side is facing the pancake. Set the edge of the plate ¼-inch from the edge of the filling and firmly press down to cut the dough. Slowly roll the plate around the pancake to trim the edge of the dough off while making a nice clean circular cut around the pancake. Repeat for the remaining dough.

Cook the pastries: Heat 2 tablespoons of vegetable oil in a shallow frying pan over medium heat. Place two turnovers or one pancake on the hot oil and let fry for 3-4 minutes until the bottom is golden brown. Reduce heat if it starts to burn or increase heat if it’s not browning. Flip the pastry (pastries) over, adding more oil if needed, and brown the other sides for another 3-4 minutes until golden. Remove from heat. Cook the rest this way. Cut the pancakes into quarters. Serve immediately or keep in the refrigerator for a few days and warm up in the oven.