Take a siakap fish and place it in a pot with 2 sticks of whole serai.
Slice half an inch of halia and 50 pieces of endau, then add them to the pot. Allow the ingredients to simmer for a few minutes until they are partially cooked.
Remove the partially cooked fish from the pot and place it in a serving dish; keep the cooking liquid aside.
Peel one-inch piece of galangal, one inch of halia, a small amount of turmeric root, 3 sticks of serai, two cloves of garlic, and four red chili padi. Also, prepare 2-3 leaves of lime rind.
Add the sliced ingredients to the reserved cooking liquid along with a small box of instant coconut milk and one small box of water.
Simmer for about 5 minutes until the coconut milk is slightly thickened and fragrant flavors are absorbed into the broth.
Stir in one tablespoon of fish sauce, salt, sugar, and seasoning to taste. Then add the steam-fish liquid from step 3 and mix well.
Place the fish back into the pot with the prepared sauce and simmer for another 5 minutes.
Serve hot, garnished with lime juice (squeeze one or two limes). Enjoy the dish with a nice aroma of serai and limau purut leaves. It is very refreshing and flavorful.