To make the Sambal Tumis Belachan:
Put the dried chilies into a sieve. Using scissors, snip the chillies and shake the sieve vigorously to remove most of the seeds. Soak the chillies in warm water until soft, then drain, discarding the water. In another bowl, soak the tamarind in 6 tablespoons of hot water for 15 minutes, until softened. Massage and squeeze to get the juices from the pulp, then strain and discard the pulp.
Open your windows. Toast the belachan in a dry pan for about 5 minutes, chopping at it with your spatula to break it up, until aromatic and powdery. You can also do this in the oven for less fuss/fewer complaints from next door.
Blend or pound the toasted belachan, shallots, chillies, garlic and lemongrass until you get a smooth paste.
Heat your wok and add the groundnut oil. Fry the paste over a medium-low heat, stirring to make sure it doesn’t stick or burn. After 20 minutes, add three-quarters of the tamarind paste, followed by the gula melaka, allowing it to slowly melt into the hot sambal. Keep stirring. The chilli is cooked when you see the oil separating from the mixture. It usually takes at least 30 minutes. Taste and adjust with more sugar, salt or tamarind paste if needed.
The sambal will keep for 3 weeks in the fridge, as long as you always dip into it with clean spoons and keep submerged under a layer of oil. Or spoon the hot sambal into hot jars and seal tightly before sterilising in hot water.
To make the Barbecued Sambal Lemon Sole:
Cut the banana leaves into pieces that are roughly the size of the fish. If you’re using fresh banana leaves, soak them in hot water to soften before wiping dry. If using frozen banana leaves, make sure they are fully defrosted and wiped dry.
Pat the fish dry and cut 3 slits diagonally across the middle to help it cook more evenly. Brush both sides with oil and season generously with sea salt. Take one sheet of banana leaf and smear with half the sambal (2½ tbsp).
Fire up your barbecue. Place the sambal-smeared banana leaf on the grill, with the sambal-smeared side facing up. Lay the fish over the sambal, dark side up. Smear more sambal over that upper side of the fish. Cover with another sheet of banana leaf and secure with toothpicks to make a parcel. Let it grill for 7-10 minutes. You should smell the fragrance of burnt banana leaves and the flesh of the fish should easily come away from the bone. Alternatively you can grill the fish in the oven with the setting turned up to high.
Meanwhile, make the dipping sauce by stirring the ingredients together.
Remove the fish from the grill and transfer it to a fresh sheet of banana leaf. Scatter coriander over and serve with the dipping sauce and lime wedges.