Combine the yogurt, chickpea flour, water, chillies and ginger. Blend in a food processor or with an immersion blender. Set aside.
In a large pan, heat the ghee, cumin seeds, curry leaves, cloves and asafoetida. When aromatic, add the yogurt mixture and stir constantly until it comes to a gentle boil on a low heat. This is to ensure that the mixture does not curdle.
When the mixture is gently simmering, add the turmeric, salt, mango puree and sugar. Adjust the consistency with water if you like, and simmer for a further 4-5 minutes. Taste to check for hot, sweet and sour flavours and adjust with salt, sugar or lemon juice as necessary.
Remove from the heat and stir in the chopped coriander.
Serve with hot basmati rice, chapattis and your favourite dry curry.