In a large bowl, mix together the minced chicken, green onion, leek, salt, pepper, sesame oil, Shaoxing wine and egg white until combined. You'll notice I use leek instead of the more traditional cabbage. I find it gives the filling a sweeter, more delicate flavour and doesn't release as much water, which means the potstickers don't go soggy. The Shaoxing wine is worth tracking down too - it adds a depth of flavour you won't get from regular rice wine or mirin.
Lay out a wonton wrapper, and put a small spoonful of the chicken mixture in the middle of the wrapper.
Using a finger dip into the egg yolk and brush the outside rim of the wrapper with egg yolk.
Fold the wrapper over, to make a half moon shape and seal the join well, and press out any air. Repeat with the other wonton wrappers.
Heat the vegetables in a non-stick frying pan with a lid. Fry the dumplings on a medium heat until golden and crispy on the base. Around 30-40 seconds.
Then pour in approximately 100mls of water into the pan to create steam. Make sure to be careful, it will sizzle and spit. Cover and cook the potstickers for around 3 minutes, until they’re thoroughly cooked through.
Mix together the dipping sauce ingredients and serve alongside the potstickers