1 red onion, halved and sliced into very thin half-moons
250g carrots, julienne sliced or coarsely grated
2 spring onions, finely chopped
Small handful coriander leaves
1 clove garlic, finely chopped
20g fresh ginger, finely chopped
3 tbsp lime juice
3 tbsp soy sauce
2 tbsp sunflower oil
½ tbsp sesame seeds, toasted
For the rub
2 nori sheets
1 tbsp coarse sea salt
1½ tbsp black peppercorns
2 tbsp granulated sugar
2½ tbsp sesame seeds, toasted
½ tbsp garlic granules
Heat/light the barbecue for direct medium heat (coals evenly distributed over the base of the barbecue). For the slaw, mix the white and red cabbage in a bowl with the salt and 1 tbsp granulated sugar. Scrunch the cabbage with your hands for about 3 minutes to tenderise it. Set aside to rest for 10 minutes, then put in a colander, discarding any drained liquid. Add the cabbage back to the bowl.
Mix the red onion, carrots, spring onions and coriander into the cabbage. In a separate bowl, whisk together the remaining slaw ingredients, then toss with the vegetables, mixing well to coat everything in the dressing. Cover and chill until ready to serve.
For the rub, cut the nori sheets into small pieces, then whizz into fine flakes in a small food processor. Finely grind the sea salt, peppercorns and sugar in a pestle and mortar. Add the nori flakes and sesame seeds and grind again until fine. Stir in the garlic granules.
Wipe the banana leaves with a wet cloth/kitchen paper. Cut off any stringy edges, then briefly move the leaves over the hot grill until they begin to turn shiny – this makes them easier to shape.
Pat the fish dry with kitchen paper, then press the rub mixture all over the fish and inside the cavity. Put each trout on a banana leaf, then wrap it by folding the sides of the leaf around the fish. Secure the leaves with wooden cocktail sticks to stop the parcels from opening up. Leave to marinate for 10 minutes.
Put the fish parcels on the barbecue, then grill for 10 minutes on each side or until the leaves are charred and the fish is cooked through (the fish will flake easily from the bones). Serve the fish parcels with lime wedges to squeeze over and the slaw on the side.