Melt the ghee in a large, deep casserole pot on a medium heat, then brown the chicken all over and set aside.
Add the onion, cumin, star anise and cinnamon to the casserole and fry, stirring, for about 10 minutes, until golden brown.
Meanwhile, put the chilli, garlic and ginger in a food processor and blend to a fine paste.
Stir this into the onions, along with some salt, the curry leaves and curry powder, and fry for a couple of minutes, until aromatic.
Tip in the tomatoes, cook for five minutes, then pour in the coconut milk and stock, and bring to a boil.
Turn down to a simmer, cook for three minutes, then toss in the potatoes.
Carefully lower the browned chicken, breast side up, into the liquid, then cover the pot and leave to cook over a low heat for an hour.
Turn off the heat and let the chicken sit for another half an hour.
Squeeze over the lime juice, scatter with the coriander and serve with roti and/or steamed jasmine rice.
