Mince garlic, ginger and preserved black beans.
Wash bitter melon, wipe dry, remove seeds and slice thinly.
Defrost fish fillets, rinse in clean water, pat dry and marinade with salt, pepper and wine.Coat with a thin layer of cornstarch, and place fillets in beaten egg.
Heat some oil, pan-fry fish fillets until golden brown. Take out and reserve.
Heat oil in wok again, fry minced garlic, ginger and black beans and green onions, put in bitter melon. Add in stock and seasonings and let cook for a while until melon is done. Add in fish fillets and stir well until sauce thickens and serve.