Using a sharp knife, slice the fish into 1" (2.5 cm) thick steak cuts. Set aside.
Prepare the curry paste:
An overview of the curry paste ingredients.
In a pestle and mortar, pound the curry paste; start with the chilies and gradually add the other ingredients, from the driest to the wet. Pound the paste to a semi-fine consistency. Set aside.
Cook the curry:
In a pot, dilute the paste with chicken stock to the desired consistency.
Bring the stock to a boil and cook it until the paste loses its rawness.
Add the fish and continue to cook on medium heat.
Add the eggplants; cook until the fish and eggplants are fully cooked.
Seasoning:
Season to a salty flavor profile using fish sauce.
Add the herbs:
Turn off the heat and add the fresh chilies, kaffir lime leaves and holy basil leaves.