Soak the whole spices in 1/4 cup of water and set aside.
Heat the oil and ghee in a large pot over medium high heat. Once hot. add onions and after 10 - 15 minutes when onions are golden, add in the soaked spices with the water. Cover and allow the spices to steam for 4 minutes. Keep an eye on the onions to make sure they aren't browning too much.
Add the chicken and saute for 5 minutes. Then stir in the Ginger, Garlic and Green Chilli. Saute for 2 minutes.
Add the salt, cumin powder and turmeric and allow to cook for 2 minutes before pouring in the tomatoes, paprika, red chilli powder and coriander powder. Allow to cook covered for 15 - 20 minutes over medium/low heat.
Pour in the water and add Salt. When the water comes to the boil, add soaked rice and potatoes. Cook on high heat and stir the rice several times.
When there is very little water remaining, turn the heat right down. Cover and simmer until the rice is cooked. This will take 15 - 25 minutes. You don't want to dry it out completely.
Garnish with fresh chopped coriander.