Grind together ingredients listed under "to grind" with 3 tbsp water to a smooth paste.
Marinate the cleaned chicken pieces with the ground masala for half an hour.
Heat oil in a deep and wide pan. Add sliced small onion. Cook till it turns golden brown, add crushed ginger and garlic. Cook till the raw smell goes, around 3-4 mins. Add chicken pieces and mix well. Add thin coconut milk, bring it to a boil. Reduce the flame to the lowest and cook till the chicken is done and the gravy is reduced.
Separate the chicken pieces from the gravy. Shallow fry the cooked chicken pieces till it becomes rich brown colour. Add gravy to the fried chicken pieces and cook till the gravy is dried and the chicken pieces are coated well with the masala.