Marinate the fish with the fish sauce.
Grind the onions, ginger, garlic and lemon grass to a smooth puree with
a food processor before adding turmeric and salt to taste. Heat a wok
with the cooking oil until smoking hot. Stir in the ground ingredients,
cover with a lid and simmer the mixture. Stir frequently with a wooden
spatula to ensure the mixture does not stick to the base of the wok.
When the ingredients are well cooked, put the fish in the wok. Cook for
about 3 minutes on each side, adding the green chili. When cooked,
sprinkle with the chopped cilantro leaves and serve hot with steamed