I would like to make the Coconut Rice from 'Kitchen'. However I can't find black mustard seeds. What could be used as an alternative?
Nigella's recipe for Tomato Curry (from Kitchen and on the Nigella website) includes a spiced Coconut Rice as an accompaniment. The rice is cooked in coconut milk and spiced with Nigella seeds. The Nigella seeds are known also as kalonji and you may be able to find them in Asian or Indian food stores. You can also buy them on-line.
The Nigella seeds are slightly pungent and biitter and Nigella suggests black mustard seeds as an alternative. If these are also difficult to find then you can probably substitute the more common yellow mustard seeds. However yellow mustard seeds are milder than the black ones so you may find that you need to use slightly more seeds to pack the same punch as the black mustard seeds - adjust the quantities according to your own taste.