Barbecuing is one of the more relaxed and convivial ways of entertaining: people tend to be drawn to the grill by the fragrant smoke that comes from the fat dripping onto the coals. If you have the grill fired up for this Indonesian dish of fish wrapped in banana leaf (which was developed by my ex-food stylist, Vivian Herijanto), you'd might as well also cook some skewers of chicken satay. Serve with Indonesian salads such as Balinese chicken salad or gado gado.
Belacan is salted, fermented and dried shrimp paste that comes in small bricks. It has a strong smell, but the flavour is muted when mixed with other ingredients. Kecap manis is Indonesian sweet, dark soy sauce. You can buy these ingredients, plus the banana leaves, lemongrass and bird's-eye chillies, in shops specialising in Southeast Asian products.
Make the sweet soy dressing. Put the belacan in a dry (unoiled) pan and place it over a medium flame. Cook until the belacan is fragrant (or more fragrant than usual) and it looks dry on the surface, turning it over as needed. Put the toasted belacan in a mortar.
Roughly chop the chillies, shaking out and discarding the seeds as you go. Slice the garlic. Put the chillies and garlic in the mortar with the belacan and pound until finely ground. (Or use a food processor). Stir in the kecap manis and lime juice.
Make the sambal matah. Use the side of a cleaver or knife to lightly crush the lengths of the lemongrass stalks, then slice them as thinly as possible.
Slice the shallot, then mince the garlic and chilli.
Heat the oil in a small pan and when it's hot, add the belacan. Stir well, then add the lemongrass, shallot, garlic and chilli. Cook briefly, just to combine the flavours and make the mixture fragrant.
Remove from the flame, then stir in the lime juice and season to taste with salt and pepper.
Heat the grill so the coals are white hot.
Make two deep slashes on each side of the fish, then season them inside and out with salt and pepper.
Rinse the banana leaves under cold water. Trim them so you have two pieces that will each fully enclose one fish.
Wrap each fish in a banana leaf to make a flat parcel. Grill over the coals for eight to 10 minutes on each side, or until cooked through. (Or cook them under the oven grill.)
Open the parcels and spread some of the sweet soy dressing over the fish. Spoon the sambal matah over the top then serve immediately.