Preheat the oven to 170ºC/325ºF/gas 3. Place a large, wide, ovenproof pan over a medium-high heat. Add the coriander seeds, cumin seeds and peppercorns, crumble in the dried chillies and toast for 1 minute, or until smelling fantastic. Tip the spices into a pestle and mortar and bash to a fine powder. Peel and roughly chop the ginger, then peel the garlic. Add to the mortar with the turmeric, 1 tablespoon of oil, the vinegar and bash to a paste.
Using a sharp knife, chop the pork belly into rough 2cm chunks. Return the pan to a medium-high heat, add the pork and season with a little salt. Fry for around 15 minutes, or until golden all over.
Meanwhile, peel and finely slice the onions. Once the pork is golden, add the curry leaves and three-quarters of your curry paste to the pan (save the rest in an airtight jar and store in the fridge). Toss well, then stir in the onions and cook for a further 15 minutes, or until golden. Finely chop the chillies, then stir into the pan with the tamarind paste and sugar. Pop the pan into the hot oven for around 25 minutes, or until darkened.
Remove the pan from the oven and skim away any excess fat (keep in an airtight jar and store in the fridge – it’s great for wok-fried greens or epic roast potatoes). Place the pan over a high heat. Add 600ml of boiling water, bring to the boil, then reduce to a simmer. Place the charcoal and cinnamon stick over a direct flame (I use my gas hob). Using tongs, turn them over until the charcoal starts to smoke and turn white. Pop the cinnamon and charcoal into a small heatproof bowl along with the cloves, then place the bowl directly into the middle of the vindaloo pan. Drizzle over a drop of oil until the charcoal starts to smoke like incense. Cover the pan with a double layer of tin foil and poke a hole in the top to allow the smoke to escape. Cook the curry for around 20 minutes, or until the meat is tender, or cook for longer until it falls apart, topping up with water if it gets too dry.
Remove and discard the charcoal, cloves and cinnamon, then serve the vindaloo with homemade naan breads, a baby gem salad and raita.