- First, prepare the fish.  Cut a few diagonal slits on each side of the fish using a sharp knife. 
- Season with salt on each side. 
- Stuff the lemongrass inside the fish. 
- Place the fish on a plate and steam, until the flesh flakes down to the bone when pulled with a fork, 15 to 18 minutes. 
- While the fish is steaming, make the sauce.  In a small saucepan, add the water, chicken stock cube and Thai palm sugar. 
- Bring the mixture to a boil over medium heat. 
- Remove the pot from heat, and add the garlic, chilies, and cilantro.  Let steep for a few minutes. 
- Season with the fish sauce, to taste.  Add the lime juice. 
- Ladle the sauce over the fish.  Serve immediately.