Prepare Dumpling skins by mixing 2-1/2 cups all-purpose flour and 1-1/4 cups boiling water in a mixing bowl with a wooden spoon until it reaches a rough dough. Knead for 5 minutes (letting dough rest if it is too hot to handle before kneading) until smooth and elastic adding flour if dough is sticky. Cover dough with a towel and let it rest for 25 minutes.
Cut each half into 20 pieces (the original recipe says 25, but I found that it made it a little to hard to roll them to the desired size.)
(Sorry I don't have any pictures of the making the filling...)
Before starting to roll out the skins, place 5 cups finely chopped cabbage (I used regular cabbage but it calls for Chinese or Napa Cabbage) tossed with 1 tsp salt in a bowl, set aside. If you are using dumpling skins - do this 30 minutes before you want to combine filling.
After the 30 minutes has passed, squeeze out excess water by taking handfuls of cabbage and squeezing. Squeeze out as much water as possible. I was actually surprised at how much water this actually brought out of the cabbage!
Mix the cabbage, with 3/4 lb ground pork (I used sausage), 2 cups finely minced leeks, and 1 Tbsp minced garlic. Mix until pork is broken into small pieces.
Next add 2 Tbsp soy sauce, 2 Tbsp Sesame oil, 1 Tbsp rice vinegar, 1 tbsp minced gingerroot, 1-1/2 tsp minced garlic and 1 tbsp cornstarch to the meat mixture. If mixture seems loose, add more cornstarch.
Take one dumpling skin in your hand (sorry blurry picture) and place 1 heaping teaspoonful into the skin.
Unless you bought the skins or cut out perfect 3-inch circles, you may have to adjust the amount of filling in each skin.
I found it helpful to rub a tiny bit of water around the edges of the dumpling skin before attempting the next steps.
Use the thumb and index finger of one hand to form small pleats along the outside edge of the skin.
Press to seal, continue making pleats until completely sealed. The inside edge of the dumpling should curve in a semicircular fashion to conform to the shape of the pleated edge.
Place the sealed dumplings on a cookie sheet that has been sprinkled with cornstarch (or on the countertop if you are like me and do not want to dirty yet another dish!)
Bring about 3 quarts of water to a boil in a large pot.
Gently add the 5-10 dumplings to the pan of boiling water.
The water will turn a bit cloudy due to the flour and cornstarch.
Stir immediately after adding dumplings to prevent them from sticking together. Bring the water back to boiling.
Add 1/2 cup cold water and continue cooking over high heat until water boils again.
Add 1/2 cup cold water again, and let it come to a boil.
And for a third time add 1/2 cup water to the pan. Cook until the water boils again. Remove dumplings from pan and drain. Cook the remaining dumplings in the same manner. (If you want a simpler method boil for 8 minutes uncovered over high heat - but be warned this method tends to tear apart the dumplings more than the traditional method.)
Serve with a dipping sauce of 1/2 cup reduced sodium soy sauce and 3 Tbsp Worcestershire sauce.