Grind the cumin, coriander, peppercorns, cardamom, cloves, and cinnamon into a fine powder.
Blend the ginger, garlic, chillies, and vinegar into a smooth paste.
Combine the ground spices with the paste, season with salt, and rub over the pork.
Marinate the pork for 90 to 120 minutes.
Heat 60ml of oil and fry the onion for 4 minutes until golden-brown.
Add the pork and fry for 7 minutes until browned on all sides.
Cover and cook on low heat for 40 minutes, adding tiny amounts of boiling water if dry.
Heat 5ml of oil in a separate pan and add the mustard seeds until they pop.
Fry the cashew nuts with the mustard seeds for 3 minutes until golden-brown.
Serve the vindaloo with rice or in tortillas, garnished with the seed and nut mixture.