Soak the chillies in hot water for about 15 minutes, then drain.
Heat a wok or heavy-based frying pan and, without adding any oil, dry-roast the cumin and coriander seeds and the nutmeg for 40–50 seconds until they release their aroma. Tip into a spice grinder and grind to a powder.
Put the powder in a food processor with all the other ingredients and wh