Scallion pancakes are best rolled very thin. I couldn't make the pancakes too thin because the lard melted easily and made a mess, causing the pastry to break and pushing the spring onions out. On another try, I used shortening (Crisco) and the results were much better.
Recently I'm crazy about scallion pancakes, cong you bing (onion oil pancakes), sometimes called Chinese pizza. I prefer them to Korean pancakes because cong you bing are more fragrant. They are also easy and quick to make and cost very little. All you need are scallions, salt, oil/shortening and plain flour. Sesame seeds are optional. Scallions are more suitable for the pancakes because they are have thicker leaves and you can still taste them after they are cooked, unlike spring onions which are thinner and delicate. Scallions, however, do not smell as fragrant as spring onions. I have pots of spring onions in my backyard so I use those instead of scallions. I also have a large patch of Chinese chives that have been growing perennially and they can be used in place of the scallions to make jiu cai bing. You can also add ground meat or even fried bacon bits, like I did here.
Scallion pancakes from street vendors in Shanghai are usually thick and about the size of a small saucer, handy for eating on the go. The pancakes from restaurants are twice as big, very thin and crispy and I prefer them to the vendor-type. Whether thick or thin, scallion pancakes are best eaten when hot. Once cold, the pancakes are heavy and soft.
Whoever came up with the flaky pastry for scallion pancakes was a genius. The dough is flattened into an 'ox-tongue' shape and oiled, then rolled and coiled. When fried, the pastry separates into layers, the outer pastry crispy while the inner pastry is soft. If the pancake is rolled thin enough, the whole pancake is crispy. Most recipes do not call for lard or oil in the flour but I do add some to make the pastry short.
You can mix the salt and oil with the scallions but the water in the scallions and the oil will dissolve the salt and give a general saltiness to the pancakes. I prefer to layer the ingredients so that I can taste a grain of salt here and there. I think the worst recipe I've come across is one where the salt is added to the flour. I also prefer to use shortening (lard is good too but tends to melt easily) because it doesn't wet the dough like oil does.
Scallion pancakes are best eaten as a light meal with hot and sour soup because the sourness cuts the oil and refreshes the palate. You can also eat the pancakes as a snack with a cup of hot green tea.
Scallion Pancakes (makes 5 to 6 large pancakes)
3 cups plain flour
1 1/3 cups boiling water
3/4 cup finely sliced scallions
medium-texture salt (I'm told that vendors add msg)
veg oil or lard or shortening (shortening is best)
1. Sieve the flour into a bowl, pour the boiling water in (leaving 2 T, as all flours have different absorbency) and use a pair of chopsticks to mix, swirling round and round until all the flour form lumps. Wait a minute if you can't handle the hot dough. Gather into a ball. If needed, add the remaining water. Mix in 1 heaped T shortening. Knead dough on a lightly floured surface until smooth. Add more flour if too soft, or more water if too hard. Overall, the dough should be soft-firm when you press it with a fingertip. Cover and leave 10 minutes or you can even continue without resting the dough.
2. Divide the dough into 5 or 6 pieces. You can also use the whole ball of dough in one go to make a long roll but I find that working with small pieces of the dough is easier. Roll one piece of dough into a cylinder and flatten into 'ox-tongue' shape (oblong) of about 1/2 cm thick. Brush veg oil or spread shortening over entire surface. (I prefer shortening because it doesn't melt too easily in hot weather so that the pancakes won't break so easily when rolled.) Sprinkle the pastry with a generous pinch of salt, followed by the scallions (but leave the furthest edge clear so that the scallions will not get squeezed out when rolled) and roll, tucking in snugly. Now coil the roll, the seam inside the coil so that it can't open. Sprinkle some sesame seeds over and flatten with your palm. Roll into a thin pancake, the thinner the better.
It's best to cook one pancake and taste it so that you get an idea of how much salt to use.
3. Heat up some oil (1/4 cup or less) in a frying pan and fry the pancakes one by one until crispy. Turn over once only. The oil must be quite hot so that the layers of pastry'll separate and puff. Cut pancake into wedges and serve hot with a dip of black vinegar and light soy sauce if like.