To make the paste, peel and finely slice the fresh turmeric, then scrub and finely slice the galangal. Place in a dry frying pan for a few minutes, or until they start to release their oils.
Peel and finely slice the shallots and garlic, then deseed and roughly chop the chillies. Slice the nuts.
Crush the peppercorns in a pestle and mortar, add all of the paste ingredients and 1 big pinch of sea salt, then bash and muddle everything together – if you’re mortar is too small, do this in batches.
Place half the paste in a sealable plastic bag and freeze for another day. Reserving 2 tablespoons of the remaining paste to one side, place the paste into a large roasting tray or casserole pan. Add the pork and massage in all those lovely flavours. Drizzle with oil, then cover with a piece of wet greaseproof paper and a layer of tin foil.
Place in the oven to cook for 2 hours, or until beautifully browned and gnarly, shaking the tray halfway through and removing the greaseproof and foil for the final 30 minutes.
Chop the Chinese long beans into 7cm chunks (if using), halve the squash across the middle, then roughly shred the cabbage.
Remove the tray from the oven and place over a medium heat on the hob. Add the vegetables, lime leaves, reserved paste and coconut milk, and gently mix together. Bring to the boil, then simmer for 10 to 15 minutes, or until the veg is tender.
Meanwhile, cook the rice according to the pack instructions, and prepare the sambal. Finely slice the chillies and lime leaves, then peel and finely slice the shallots. Trim and remove the outer leaves from the lemongrass, then finely slice. Add to a small bowl with the lime juice and a drizzle of coconut oil. Season to taste.
Cut the banana leaf (if using) into pieces slightly larger than your bowls or plates, then hold over the flame on your hob until bendy and pliable.
Spoon the rice onto the banana leaves, season the curry to taste, then portion up. Serve with the sambal and lime wedges for squeezing over.