In a large frying pan, heat a couple tablespoons of oil, once heated add the paste and fry until it becomes slightly golden brown.
Add the stock and stir to mix.
Place in the lemon grass and leaves and let simmer just until it begins to thicken.
Add the fish and let cook for a minute or two, then gently flip over.
Add the coconut milk and gently stir to mix.
Once the fish has finished cooking, remove the kafir leaves and lemongrass and slide into a dish for serving.