Shiitake and Pickled Mustard Greens Dumplings

Ingredients

• 1/2 tsp toasted sesame oil
• 2 tbsp dark soy sauce
• 2 tsp Chinese black vinegar
• 12 circles of dumpling pastry
• 4 large (dried shiitake)
• 1 spring onion (finely chopped)
• 1/2 bulb pickled mustard greens (finely chopped - the kind you find in international supermarkets in plastic vacuum packs)
• 1 tsp light soy sauce
• 1/2 tsp shaoxing rice wine
• Pinch chilli flakes (I use gochugaru)
• pinch white sesame seeds
• greens of a spring onion (finely chopped)