For the filling of the gyoza, I used one Chinese cabbage (just the leaves), 2 spring onions, 250 grams (dry weight) of rehydrated shiitake mushrooms, 3 cloves of garlic, a 1″ piece of ginger and 2 carrots. To this I added a bit of mirin (about 2 tablespoons), soy sauce (about 2 tablespoons), sesame oil (about 1/4 teaspoon) and salt (about 1/4 teaspoon).
I used pre-made dumpling wrappers. The gyoza were pan-fried on both sides, then I added some water and cooked them until it evaporated. I served them with spring onion, rice vinegar, soy sauce and chilli oil.
Any extra dumplings can be frozen before cooking to save them for later.