Put the mangoes in a large bowl.
Put all the ingredients for the tempering in a blender and process until ground.
Set aside.
Heat the oil in a heavy-based pan over medium.
Add the spices and sugar and Stir-fry for about 1 minute.
Add half to the chopped mangoes, then put them into sterilized jars.
Add the tempering to the jars and pour in the remaining spiced oil, then cover with the lids and keep for 3 days in a cool, dry place.
On the third day, put the jars in a sunny or warm place for 2 hours.
With the lid tightly fitted, turn the jars upside down, then straighten and keep the lids well closed.
This chutney can be stored in a cool place for several months