Add diced cabbage to a fine mesh sieve and toss with ½ teaspoon salt. Place over a bowl and let sit for 20-30 minutes then press cabbage down with a rubber spatula quite a few times to squeeze out excess moisture. Set aside.
Add egg yolk to a large bowl and whisk. Add all remaining filling ingredients (including cabbage) and mix with your hands until thoroughly combined.
Line a baking tray with parchment paper and prepare some damp paper towels or a damp cloth. Keep all wrappers covered in plastic wrap when you are not using them. Fill a small bowl with water..
Working with 2-4 wrappers at a time (depending on how fast you are), add 1 tablespoon to the middle of each wrapper. Dip your finger in water and run it around the edge of half of the wrapper. Fold wrapper over in half to create a half-moon shape and pinch the edges firmly together to seal. Place filled wrappers on the prepared baking tray and cover with damp paper towels/cloth. Repeat with remaining wrappers
Heat 1 tablespoon oil in a large skillet (that has a lid) over medium-high heat. Add about 12 gyoza to skillet flat side down, enough that will comfortably fit. Cook without touching until the underside is lightly golden (approx. 2 minutes).
Stand back and use one hand to hold the lid as a shield, as you pour 1/3 cup water around the pot stickers then quickly place the lid on. Turn heat to LOW and cook until water has completely evaporated. Remove lid, increase heat to medium and cook 1-2 additional minutes to crisp up bottoms. Transfer potstickers to a paper towel-lined plate or baking tray. Repeat until all potstickers are cooked. Best served warm with Dipping Sauce.
Gyoza wrappers are round wrappers located in the refrigerated section. If your grocery store doesn’t have them then you should be find them at your local Asian Market.