To Make Filling
- Add the cabbage and salt to a large bowl and thoroughly mix together. Let the cabbage sit at room temperature for 15 mins.
- Transfer the cabbage to a clean kitchen towel or cheese cloth. Roll up the cloth and wring out the liquid in the cabbage, like you’re wringing a wet towel. This is a key step so that the gyoza doesn’t become watery. Wring out as much as possible. Do this in batches if it’s easier.
- Add the wrung out cabbage, chives, garlic, ginger, pork, soy sauce, 2 tbsp of the sesame oil, black pepper, salt, sugar, and potato starch to a large bowl.
- Use your hands to mix the ingredients together for about 2 mins. Mash and mush the ingredients together, squeezing it through your fingers so it turns into a sticky filling that will hold together when you spoon it into a dumpling skin.
To Make Gyoza
- Prepare a tray by lightly dusting it with potato starch. Place a gyoza skin in the palm of one hand with the floured side down. (The skins are sold with one side floured.)
- Dip a finger in the potato starch solution and wet the entire edge of the skin. This water starch mixture is the “glue” that will hold the skin closed.
- Add about 1-2 tbsp of the filling to the center of the skin. Use the index fingers and thumbs of both hands to fold the skin and pinch it together. Place the completed gyoza on the tray, fold side up. Repeat until you’ve used up all the fillings.
To Make Dipping Sauce
- Combine the soy sauce, vinegar, and rayu. Adjust to your own taste.
- Pour the dipping sauce into individual small bowls and set aside.
- Heat a non-stick pan or cast-iron skillet over high heat for about 5 mins. When the skillet is hot, add 1 tbsp of the sesame oil, making sure the entire surface is coated.
- Begin adding the gyoza one at a time, in neat rows, the seam up. A 12-inch skillet will hold about 20 gyoza. Once all the gyoza are added, fry them for about 10 secs. Now quickly pour in the water over the gyoza and cover the skillet tightly.
- Cook over high heat for about 4 mins. Uncover the skillet, there should be little or no water remaining. Cook for another 1 min. Drizzle the remaining 1 tbsp sesame oil over the gyoza and cook for an additional 1 min. The gyoza should look glossy with the skins cooked through.
- Turn off the heat and use spatula to transfer the gyoza to a serving plate, this time with the seam side down (you want to show off the beautifully crispy, browned bottoms of the dumplings). Serve the dumplings steaming hot, with the dipping sauce on the side. Dip in the sauce to eat.
- You can substitute the salt and soy sauce in the gyoza filling with 2 tbsp of red miso, for a savoury twist.