Chop finely nappa cabbage. You can use a food processor if you want.
Sprinkle salt on the nappa cabbage in the bowl, mix them lightly, and let them sit for about 10 minutes. Squeeze water out of the nappa cabbage with a kitchen clothe or kitchen towel.
Put all the ingredients of Filling A in a big bowl and mix them until they become paste like. It will take at least a few minutes.
Add Filling B ingredients into the bowl and mix all well. If you have time, let it sit in the fridge for 1 hour. In that way, it will taste better.
Scoop about 1 tbsp of the mixture onto a dumpling/gyoza wrapper with a knife or spoon and fold it over.
Mix flour and water in a cup. You will use it in the next step.
Put the salad oil in the heated non-stick pan , and put the dumplings. Pour the flour dissolved water and place the lid on. Keep the flame medium-low.
When the water has almost evaporated – usually after 8 or 9 minutes, pour a little sesame oil (or salad oil) from the edge of the pan, and move the pan around slightly so that each of the dumplings’ bottom gets a little bit of oil. Place the lid on, and turn the heat high. Cook the gyoza until the bottom gets crisp.
Find a round plate that’s a little smaller than the pan’s opening diameter. Put the plate on top of the gyoza, and flip the pan with the plate so that all gyoza ends up on the plate. (I will make a video to show how to do it in the future)