Wash and pat dry the chicken pieces. Marinate the chicken with all the items (listed under the marinade section) and refrigerate for at least 2-3 hours.
Heat oil, add a tsp sugar; when the sugar starts to caramelize, temper with the whole spices. When the spices start to release their aroma, add the marinated chicken and slow cook on medium heat till the water almost dries up.
Now add the chopped tomatoes, salt, sugar and fried potatoes and continue cooking on medium heat till the masalas release oil and the chicken pieces become tender.
Add 1 1/2 cup of warm water and bring the curry to a gentle simmer. Adjust the salt and sugar.
Throw in a couple of green chillies if you want more heat and a generous dollop of ghee.