Nature's Own Whole Spices Mustard is invaluable in terms of adding depth to the baseline flavour of any dish. It is pungent and potent with a nutty flavour adds another layer to the flavour profile. In combination with curry leaves, black mustard seeds give off the aroma that all of us identify as 'South Indian'. As an oil seed, this can be used on its own to temper dishes or as a spice by mixing and grinding with water or vinegar.