Separate dough into 2 portions. Form into long sausages, about 1 inch diameter. Cut sections every 1cm. Form sections into balls and use rolling pin to form into round, flat skins about 3 inches diameter. If they are too thick, the jiaozi will be very doughy. Modify sizes of balls as appropriate.
(The other way to make skins is to buy "JiaoZi Pi" in the local Chinese store!)
Let sit while you prepare the vegetables and other additional ingredients. All need to be finely minced. Use a food processor if you have one. If you don't, I hope you have a LOT of patience. If the bits are too large, the jiaozi will fall apart.
Stir them slowly into the meat mixture. For now, add only the lower numbers (eg. 8 celery, not 10). Don't let the mix get too moist.
Test scent. It should be very aromatic. If not, add a little more brandy, or sesame oil, or onion. Test consistency. Fry a teaspoon or so of the mix. It should stick together very easily. If it falls apart, it could be because (a) the mix is too dry in which case add more veggies and/or oil, or (b) because its too moist in which case add a little more meat. (Since its easier to add more veggies, that's why I suggested adding the veggies slowly!) Test flavour. (Eat the fried bit). Your entire tongue should get a little bit of life. If necessary, add a few spices to supplement -- savoury gets central tongue, white pepper the back, black pepper the front, paprika the sides.
Fiddle until you're happy.
Take about 1 tablespoon filling and place into centre of skin. Bring one half up to meet the other half. Seal thoroughly. This usually means creating "pleats" in one half and gluing them to the other (use a tiny bit of water if you need to), If they're not well sealed, they fall apart when cooking.
Bring large pot of water to boil. Add enough jiaozi to cover the base of the pot about 1.5 times (about 25 in a 12" diameter pot, about 50 in a good size wok). Cover.
When it comes to a boil, add 1 cup cold water. Cover. Repeat. When it comes to a boil for the third time, they are ready to serve.
Note: if you stop it before the third boil, the meat will not be cooked through. Also, if you don't add cold water each time, the jiaozi will fill up with air and explode.
Alternate cooking method:
After you've boiled them, you can fry them. This is a wonderful way to serve the leftovers, and a very common Chinese breakfast!
Typically eaten with a sauce constructed of soy sauce, vinegar, and sugar. (ratio about 1/4 cup SS: 1/4 cup Vinegar: 1 teaspoon sugar). Also good with plain malt vinegar. To ensure that the sugar has dissolved completely, heat briefly. For more flavour, add a little sesame oil, hot oil, maggi (available in most chinese stores), and/or chilli pepper as you wish.
JiaoZi keep very well in the freezer. To freeze, place on trays so they are not touching (if they touch, they will stick together). Freeze overnight. The next day, place into plastic bags & seal. Will keep indefinitely.
From the Dinner Co-op