Heat 1 teaspoon Oil in a large pan over a low heat. Add 1 Onion and cook for 5 minutes.
Add 1 teaspoon Garlic and ginger paste. Cook for a further minute.
Add 1 teaspoon Garam masala, 0.5 teaspoon mustard seeds and 1 pinch Red chilli flakes (if using). Season with a little salt and cook for 2 minutes.
Add 2 Large mangoes, 200 g Sugar and 125 ml Distilled white vinegar.
Bring to the boil then reduce to a simmer.
Simmer uncovered for an hour. Mash any of the larger mango chunks with the back of a wooden spoon or potato masher.
Notes
The best way to tell if a mango is ripe is by the feel of it. Give the mango a gentle squeeze and it should give slightly which means that the flesh inside is nice and soft. It is similar to checking if a peach is ripe.
If you want to speed up the process of ripening a mango, then you can put them in a brown paper bag and leave it undisturbed overnight. This will allow it to release some ethylene, which is an odourless gas that speeds up the ripening process. Remove the mangoes from the bag once they start giving off a fruity smell and softened.
We love a really thick and chunky chutney. However, if you wanted it smoother, then you could blend it.
If you want to give these as gifts, then you will need to store them in sterilised jars.
Try to let the chutney sit in the fridge for a few hours before servings, as it allows time for the flavours to come together.