Prepare the dumping wrappers (see Tip to use store-bought wrappers): Whisk together flour and baking powder in a large mixing bowl. Add 1 cup plus 2 tablespoons cold tap water and stir with a wooden spoon or rubber spatula to combine. Keep the dough in the bowl and use your hands to knead it until all of the shaggy pieces of dough come together. The result does not have to be smooth, since the dough will absorb the water and become softer as it sits — you just need to make sure the dry flour bits have been incorporated. Wrap the dough with plastic wrap and let it rest at room temperature for at least 4 hours or overnight.

While the dough rests, prepare the filling: Combine the pork, garlic chives, egg, sesame oil, soy sauce, sugar and 2 teaspoons salt in a large mixing bowl. Mix to combine with a wooden spoon. Cover and refrigerate until ready to make the dumplings.

Once the dough has rested for at least 4 hours, on a clean surface (lightly dusted with flour if the dough seems sticky), pat the dough into a rough rectangle and cut into 4 equal pieces. Roll each piece into a log about 14 inches long and then cut each into 1-inch lengths. If needed, dust the dough with a generous amount of flour and toss to coat. Repeat with the remaining dough, covering it with plastic wrap as you proceed. You should have about 56 pieces of dough.

To roll the wrappers, working with one piece at a time, press the dough down onto the work surface using the palm of your hand, then press into a 1- to 2-inch circle. Using a wooden dowel, start at the edge of the dough and roll to the center and back out. Rotate the dough and repeat, working your way around the circle, until the dough is about 4 inches in diameter. Set aside your dumpling wrapper on a lightly floured surface, loosely covered with plastic wrap, and repeat with a few more pieces, then proceed to make some dumplings.

To fold the dumplings, take a wrapper and place it in the palm of your hand. Spoon a rounded tablespoon of the filling into the center and fold the dumpling in half (you should have about ¼ inch of space surrounding the filling at the edge of the wrapper). Using your fingertips, make pleats to seal the filling inside the dough. There is no right or wrong way to pleat a dumpling. An easy way to start is first fold it in half around the filling, creating a half-moon shape. Then, press the edges together at the top-center of the seam to seal. Now start to make small folds on either side of the center point until the entire seam is pleated.

Place each formed dumpling on a flour-dusted plate or tray and repeat with remaining wrappers and filling, keeping them draped with a sheet of plastic wrap to prevent them from drying out. Continuing to work in small batches, roll out a few more wrappers and make more dumplings. (To freeze the dumplings, see Tip.)

To cook the dumplings: Heat a medium lidded skillet on medium-low. Add 1 tablespoon oil, place 10 to 12 dumplings in the pan, add ¼ cup water, cover the pan and steam-fry the dumplings, untouched, 8 to 9 minutes, until the bottoms are golden brown and the skins are slightly puffed up. Remove and repeat with more oil, water and dumplings, wiping out the pan between batches as needed if the oil is becoming too dark.

Serve the dumplings immediately, with a combination of rice vinegar and soy sauce (mixed to taste) for dipping.