Spinach and Egg Dumplings

To make the dough:

1. Add the flour to a wide mixing bowl and stir in the salt.
2. Stir in the water and egg white with your fingers. The flour will look shaggy, like biscuit dough; as the dough comes together, run an open palm around the edge of the bowl and fold the flour in the center, spinning the bowl with your other hand as you go, until it all forms a rough clump. It's fine if there are still pockets of dry flour.
3. Coat your work surface with a fine dusting of flour and turn the dough out of the bowl. Dust your hands with flour and shape the dough into a fat log about the width of your hand. Knead the dough by pushing your hands and wrists into the log and rolling it forward. Then roll it back and push again. Repeat a few times until the log moves easily, adding more flour if it sticks, then spin the log 90 degrees, shape it into a horizontal log again, and knead a few more times, adding more flour if necessary. Use no more flour than you need to keep the dough from drying out.
4. As you knead, the dough will get firmer and tougher with a texture reminiscent of a gummy bear. It's ready when it's smooth to the touch, like the surface of a pearl, not tacky, with no cracks or pockets of dry flour. There may be some lumps.
5. Put the dough back in your work bowl and cover it with a sheet of plastic wrap. Let it sleep for 15 to 30 minutes. While it relaxes, you can prepare your filling.

To make the filling:

1. Bring a medium pot of water to a boil over high heat. Add the spinach and cook for 30 seconds, until it turns a vivid green, then, using a slotted spoon, transfer it to a bowl of ice water.
2. Chill thoroughly and drain. Wrap the spinach in a clean cheesecloth or tea towel to wring out excess moisture, then roughly chop it and set it aside.
3. In a small bowl, whisk together the eggs, milk, and 1/4 teaspoon of the salt and set aside.
4. In a medium nonstick skillet, heat the vegetable oil over medium-low heat until a few drops of water added to the pan sizzle and evaporate. Pour in the egg mixture and cook, stirring occasionally, for 4 minutes, just until the eggs form fluffy curds but have not fully set; they should still be slightly runny. Remove from the heat and let cool in a medium bowl.
5. Use your hands to gently fold the eggs, sesame oil, oyster sauce, remaining 1 1/4 teaspoons of salt, and pepper together until fully combined. Gently fold in the spinach and mix until fully incorporated.
6. Dust your work surface with a little more flour, then knead the dough as before. Work out all those lumps; after kneading about ten times you should have a satin-smooth dough that forms a clean ball you can easily push into, like the gel of a shoe insert.
7. Form your dough into a log, dust a dough scraper with a little flour, and cut the dough into four sections.
8. Roll each section into a log and chop it into six pieces for a total of twenty-four balls of dough, each about an inch in diameter. Toss the balls with a light coating of flour and cover with a lightly moistened towel.
9. Gently smash the balls of dough into flat disks, then lightly roll an Asian-style rolling pin across them to flatten them out a bit more.
10. Hold one disk by its edge and firmly but gently roll your pin from the disk's edge to its center. Roll the same edge a few more times, using more pressure at the edge than at the center. Use your other hand to turn the dough disk and reveal a new edge of the disk; roll again. Continue until all edges are rolled out and the wrapper is about 3 to 4 inches in diameter.
11. Hold your rolled-out wrapper up to a light. If you can see through it faitly, your wrapper is ready to go. Otherwise, keep rolling. Roll the edges to half the thickness of the center of the wrappers.
12. Bring a large pot of water to a boil.
13. Holding a wrapper in your palm, use a fork to add about 1 tablespoon of the filling to the center of the wrapper, then lightly pat down the filling with the fork to get rid of any air bubbles.
14. Fold the dumpling into the round yuan bao shape- Once the filling is in place, cradle the wrapper in one hand, fold the edge closest to you over the filling, and pinch the dumpling shut.
15. Now seal it for good: cradle the dumpling in your palms, clasing the sealed edge between your thumbs and index fingers, and squeeze it shut while pushing inward, making sure to squeeze out any air bubbles. The dumpling's belly should form a teardrop shape between your thumbs, which will create the round yuan bao shape.
16. Inspect the dumplings for any fissures that could rupture during cooking and pinch them shut, leaving as little open space as possible between the filling and the sealed edge of the wrapper. Repeat with the rest of the wrappers.
17. Working in batches, add the dumplings to the pot, 6 at a time. Boil for 2 minutes on high, then reduce the heat to medium-high and cook for 1 minute, then reduce the heat again to medium and cook for 2 more minutes. The dumplings are ready a minute or so after they rise to the surface; their skins will turn puffy.
18. Using a slotted spoon, gently transfer the dumplings to a plate and serve immediately. Bring the water back to a boil over high heat and repeat with the remaining dumplings.