Heat olive and sesame oil in a large pan, add chopped onion, spring onion and chopped coriander stalks and the crushed garlic and ginger. Fry gently until soft. Add eggplant and mushrooms and cook until everything is tender.
Add the juice of the lemon, the Shaoxing cooking wine, Chinkiang vinegar (or rice wine vinegar), Sriracha sauce and soy sauce. Cook to incorporate liquid. Season with pepper and lemon zest. Cool, then add fish and the chopped coriander. Mix together. Make up dumplings as described below.
Dumpling assembly
Brush dumpling wrappers with the thin egg wash.
Add 1 Tbsp of filling to the centre of each wrapper, then fold over and crimp into a sealed dumpling, according to your style (experiment with different shapes for each flavour).
Steam dumplings in a steamer basket or pot, lined with baking paper greased with a little sesame oil, until translucent and firm. Serve immediately with a dipping sauce of equal parts soy, Sriracha, sesame oil, citrus juice and sesame seeds.