Prepare all of your ingredients. Slice the eggplants into quarters, the bell peppers into thin strips, and the kaffir lime leaves into thin ribbons. Remove the basil leaves from the stems. Wash the young peppercorns. Cut the fish into bite-sized pieces.
Open a can of coconut milk and gently scoop the top layer of cream (~⅓ cup) into a saucepan. Save the thinner milk at the bottom of the can for later.
Heat the cream over medium high heat until it starts to separate into a top oily layer and bottom milky layer. Then add the curry paste and cook for 2-3 minutes.
Add the eggplant and the rest of the coconut milk and water and bring to a simmer. Cook mostly undisturbed until the eggplant is close to done.
Then add the fish, bell pepper slices, kaffir lime leaf ribbons, and green peppercorns and cook until the fish is done and the bell pepper slices are just tender. Season with fish sauce and sugar to taste.
Add the Thai basil and remove from the heat. Serve with jasmine rice.