In the same pan where you roasted the garnish ingredients, add extra oil if necessary. Add the sliced onions for the chicken curry and saute till they turn translucent.
Add the marinated chicken pieces and mix well. Add salt, cover with a lid and cook for 5-8 minutes.
Meanwhile, grind the grated coconut to a very smooth paste using as little water as possible.
Add yogurt, ground coconut, mint leaves and cilantro to the chicken. Stir to mix everything well. Cover with a lid and cook till the chicken is well done.
When the chicken is cooked, you may have a lot of stock in the pan (though you have not added any water). Using a ladle transfer this stock from the pan to a measuring cup (this stock will be used later to prepare the ghee rice). Remove enough stock , but not all of it. We would still need some stock remaining in the chicken gravy to boil it further. (See Recipe Notes)
Bring the chicken gravy to a boil again and remove from heat.
Prepare ghee rice
Heat butter/ghee in a pan and add soaked and drained rice and saute it for 2-3 minutes.
To cook the rice you would need 4 cups of water (for every cup of rice, you need 2 cups of water). You can re-use the stock you had removed from the chicken gravy (step 5 of prepare the chicken gravy). Add additional water to make it 4 cups (for e.g., if you had removed 1 cup of stock from the chicken gravy, then you would need 3 additional cups of water to make it 4 cups). Along with the stock & water, add salt and the soaked saffron (along with the milk) to the rice.
Transfer the above mixture to the rice cooker bowl and cook in the "white rice" setting. When the rice is cooked, "fluff" it gently using a fork.