It has a lovely chilli warmth and a depth of flavour thanks to mustard seeds and garlic. Adding a little mango or apple adds a fruity tartness.
Once you’ve got kasundi in the fridge, you’ll never want to be without it. Eat it with any barbecued meats, on fried eggs or slathered on a cheddar sandwich. It’s also nice with aged gruyere on toast or even spooned over steaming rice with a good dollop of yoghurt and a large handful of freshly picked herbs or cresses.
Warm the vinegar in a small saucepan and add the mustard seeds. Let sit for 15 minutes. Tip the vinegar and mustard seeds into a blender with the ginger and garlic and blend until quite smooth.
Heat the oil in a medium saucepan over high heat for 1 minute. Take off the heat for a moment, then add the cumin, turmeric, coriander, nigella, cloves and chilli powder. Fry for 20 seconds then add the mustard seed mix, chillies and onion. Bring to a simmer over a medium heat then add the tomato, mango or apple, sugar and salt.
Reduce heat to low and simmer gently for 1 hour, stirring occasionally, then pour into clean jars.