Soak the mangoes in water for 15 min. Take each mango between both hands and press evenly to soften. Squeeze around the stem to soften and cut a small hole in it, removing the stem. Place a large colander on a baking dish, squeeze or roll the mango juice out of the fruit between both hands. Use the back of a spoon to squeeze out any pulp remaining in the strainer, as the mango juice should not contain any fibers.
Beat the yogurt with a fork until completely smooth. This will prevent it from curdling during cooking.
Stir the chickpea flour in a small baking bowl with water (1) until it forms a smooth paste, it should not have any lumps.
Stir mango juice, yogurt and chickpea flour thoroughly in a saucepan with a whisk and strain through a sieve. Pour in water (2) and fold in ground ginger and asafetida.
Puree the grated ginger and chilies in a hand mixer and add to the mango-yogurt mixture form. Stir in salt and gently toss over low heat for 15 min, stirring occasionally. Simmer in the mango peels and stones to taste.
Heat the oil in a very small frying pan and fry the cumin seeds in it for just 10 seconds. Add the curry leaves and fry for 6-7 seconds. Stir the pan contents into the curry mixture. Simmer on low heat for another 15 min, stirring occasionally.
Add to taste with a