In a pan, heat the mustard oil until its slightly smoky. Switch off the stove and let the oil cool for a minute. Then, temper it with whole spices and dried red chillies. Fry the spices on low heat for 10–15 seconds, taking care not to let them burn.
Add the diced mangoes to the pan, followed by all the ginger paste (you can used chopped too), ground spices and salt. Sauté everything together on low heat for a minute, this allows the mangoes to soak up the flavors.
Saute the mangoes for a minute on low heat along with the spices.
Next, add the sugar and ½ cup of water. Don’t add too much water at this stage since mangoes tend to release moisture, and the sugar also draws out juices.
Bring the mixture to a gentle boil, then cover the pan with a lid. Let the mangoes cook covered on low heat for about 10–12 minutes, or until they soften but still hold their shape. Stir occasionally to make sure nothing sticks to the bottom of the pan. Add water if needed.
Once the mangoes are tender, remove the lid, lightly smush a few pieces(optional). Add the black salt and vinegar and taste for seasoning. At this point, you can adjust the salt, sugar, or spice levels to your liking. If the mixture looks too thick or starts sticking, add a splash more water, just enough to loosen it slightly without making it watery.
Continue to simmer uncovered for another 2–5 minutes so as to allow the chutney to thicken and the flavors to deepen. At the end of cooking, the mangoes should look glossy and well-coated in the spiced syrup.
Turn off the heat and let the chutney cool down completely. It will continue to thicken as it cools.
Store the cooled mango chutney in a clean, dry jar. It keeps well in the refrigerator for 2–3 weeks.Enjoy! Serve with flatbreads, curries, pakoras, sandwiches, and more!