In a food processor, blend together the chillies, garlic and coriander/cilantro with a pinch of salt. Add a touch of water if you need to loosen the mixture to allow the processor to produce a fine paste.
Heat the oil in a saucepan over a medium-high heat. Once it starts to shimmer, add the cumin and mustard seeds. As soon as they finish popping but before the cumin seeds turn dark brow