This year, I tried to take my crimping skills to the next level by watching this video. My technique isn't perfect, but I get the job done. You can also use pre-made gyoza wrappers instead of making your own dumpling skins.
2½ cups all-purpose flour
1 cup water
1 yellow onion, chopped
1 tablespoon fresh ginger, peeled, minced
2 cups shiitake mushrooms, stems discarded, caps halved and sliced
2 cups Napa cabbage, shredded
1 cup shredded carrots
1 cup chopped Chinese chives or scallions
1 teaspoon freshly ground black pepper
1 tablespoon soy sauce
1 teaspoon sesame oil
1/4 cup chopped cilantro
Salt to taste
Vegetable oil, for frying
Soy sauce, for dipping
Rice vinegar, for dipping
For the dumpling skins, put the flour in a medium bowl and gradually add the water, stirring with a fork until the dough can no longer be stirred. Turn the mixture out onto a lightly floured surface and knead with floured hands until smooth, 5 to 10 minutes. If the dough is too dry to come together, add a little more water. If the dough is too wet and sticky, add more flour as necessary. Transfer the dough to a clean, oiled bowl, cover with plastic, and refrigerate for at least 30 minutes or up to 3 hours.
In a large sauté pan or wok, heat the oil over medium heat and sauté the onions and ginger until softened, about 3 minutes. Stir in the mushrooms and cook for a minute. Next, add the cabbage, carrots, and Chinese chives. Season with salt and pepper. Cook for 3 to 5 minutes until the vegetables are soft and all excess liquid has evaporated. Transfer the mixture to a bowl and let cool. Stir in the soy sauce, sesame oil, and chopped cilantro. Store covered in the refrigerator until ready to use.
Cut the dough into 8 wedges with a sharp knife or bench scraper. With your hands, roll one piece of dough into a 1-inch thick rope. Cut the rope into 1-inch pieces and roll them into balls. With a rolling pin, roll out the balls into 3½-inch rounds. If your circles aren't coming out very circular at first, don't worry, you'll get better with practice. Keep the remaining dough covered to keep it from drying out.
For each wrapper, put 2 teaspoons of filling in the center and fold the dough over to form a half circle. Pleat and press the edges together with your fingers. If they don’t stick, use a little water in between to seal. Transfer the dumplings to a floured baking sheet and cover with plastic. Freeze on individual trays until completely frozen, and then store in freezer bags until ready to use.
To pan-fry, heat 3 tablespoons of vegetable oil in a large skillet over medium-high heat. Working in batches of no more than 8, add the dumplings with ½ cup water, cover, and cook until the bottoms begin to brown, 7 to 10 minutes. Reduce the heat to medium-low and continue cooking, covered, until the bottoms are toasty brown and crisp, 7 to 10 minutes more. If they should stick to the pan, carefully loosen the bottoms with a spatula (be careful not to splash hot oil on yourself). Transfer the dumplings to a plate. Serve with a dipping sauce made from equal parts soy sauce and rice vinegar.