1. Peel the skin of the mangoes and cut them into cubes.
2. Put the chopped mangoes in a pan with enough water to cover them.
3. Cook till soft.
4. Remove the pan from heat and let the mangoes cool down.
5. Transfer the mangoes in a blender along with mint leaves and blend to make smooth puree.
6. Add sugar, roasted cumin powder and black salt to the mango pulp and blend again till sugar dissolves, takes 10 -15 seconds.
7. To the puree, add 5-6 cups of water and blend well.
8. Chill for a few hours.
9. Pour in serving glasses.
10. Add some ice cubes if not well-chilled.
11. Garnish with mint leaves.
Note: For a better taste, roast keri on tawa till tender instead of boiling it.