When the mustard seeds have popped, add the onion, ginger, and cashew nuts
for 4 to 5 minutes, or until the onions
are golden brown.
Add the garlic, green chiles, and salt, and fry for 1 to 2 minutes, stirring often, or until the garlic has softened. Add the chicken pieces, and fry for 5 to 6 minutes, or until golden brown.
Add the yogurt
, stir well and bring the mixture to a boil. Reduce the heat until the mixture is simmering, then cover the pan with a lid and simmer, stirring occasionally, for 10 to 15 minutes.
Add the water, stir well, then cover the pan again, and simmer
the mixture for another 15 minutes, or until the chicken is tender and the sauce
Add the remaining ingredients, stir well, and continue to cook for 2 to 3 minutes, or until the mixture has warmed through. Serve immediately.