锅贴 has been one of my favourites other than 小笼汤饱, they are addicitive especially dipped with vinegar and some thinnly sliced ginger. If you wiki, you will realise that there are many names for this dish - 饺子, 锅贴, gyoza, bánh chẻo, momo, etc. and are widely prepared in many places - China, Japan, Vietnam, Nepal, etc. Even Italian have something similar, that is their riavoli. Talk about simple dish with innovations! We probably will get many more permutations of 'dumplings' with everyone's concoctions of fillings - vegetables, beef, pork, mutton, fish, scrimps, etc. and serving/ cooking style. 
These days, we can easily get them from the chinese dim sum restaurants, foodcourts, food centre, and frozen ones at the supermarket. If you need to gobble many pieces like me, my hubby & little boy, it can be pretty expensive especially eating in a nice restaurant. Of course, nothing beats home-made!
I'm lucky to get 2 authentic chinese shi-fu to teach me to make this dumplings. Looks easy but it does require some skills in rolling the skin and even mixing the fillings! What's even tougher for me to do it the next time is that there's no recipe as it's all based on 'feel' and 'sight'. Hopefully my 'eye-power' and estimation of ingredients will turn out my next experiment a successful one!
Potstickers/ Dumplings/ 锅贴
(makes about 100 pieces)Ingredients/ Method
Wrapper
1 kg plain flour
2 eggs
Water
1) Mix the ingredients for skin and knead till it comes together. Leave some flour aside to flour the working area later.
2) Rest dough for 20 mins and knead again to make it smooth.
Fillings
750g cabbage (高丽菜), thinnly sliced
390g spring onion/ scallions (青葱), chopped into small pieces
700g minced meat/ loin (五花肉) or pork belly
Seasonings
chicken stock cube/ msg/ oyster sauce
salt
sesame oil
cooking oil (abt 1/2 -1 cup)
pepper
dark soy sauce (optional)
1) Mix all fillings ingredients till well mixed.
2) Add in seasonings to taste.
3) Continue to use hand to mix the fillings till it becomes 'sticky'. Trick is to let the 'natural' oil from pork to bind the fillings.
Wrapping the dumplings/ potstickers
1) Flour the working area and rolling pin.
2) Take some dough and roll them like dough stick, about 2 cm in diameter, and cut them at about 1 cm mark.
3) Roll them lightly into small balls. Take one ball, lightly indent to flatten. With your thumb holding at the centre of the dough, and rolling pin on the other hand, rotate the dough and flatten at the same time.
4) Continue with the rest of the dough. Do not stack the wrappers as they will stick.
5) Scoop about 1 heap of fillings in the centre of the wrapper and fold them into half, and seal the wrapper.
6) Freeze the dumplings in the freezer if not eating them immediately.
Cooking the dumplings/ potstickers
A) Pan fried
1) Heat up a flat non-stick plan and add some oil. Arrange the dumplings neatly on the pan. When done, add water covering about 2mm of the dumplings.
2) Cover the pan and let it cook for about 6-7 mins using small heat.
3) Ready and serve.
Note: Do not de-freeeze the dumplings before cooking. Cook them in frozen state.
B) Boil
1) Boil a pot of water and put in the dumplings.
2) Continue to let the water boil and add in 1 cup of room temperature water. Repeat this step for another 2 times.
3) When the dumplings are cooked, drain them.
4) Serve by drizzling some sesame oil and light soya sauce.
