Make 3-4 diagonal slices along each side of the fish. Sprinkle the cavity of the fish with salt.
Bruise the lemongrass with a back of a knife and fold up and place into the cavity of the fish.
Mix the stock with the garlic, Thai chillies, lime juice and light soy sauce. Place the fish on a plate and pour the chilli lime mixture over the fish.
When the steamer is ready place the fish and plate into the steamer. Steam until the fish is cooked; about 20 minutes. You can check if it is cooked by inserting a knife along the backbone. If the meat pulls off the bone it is done.
To serve, place the fish on the plate in the centre of the table for all to enjoy. Spoon the broth left on the plate over the fish to make it glisten. Serve with jasmine rice.
This works well with any whole fish you have bought or caught but works best with a flaky white fish such as tilapia, fresh water trout or snapper.