Blend the gravy ingredients to a curry paste with one glass of water and then boil it for half an hour.
While the gravy is boiling, grind all the garam masala ingredients together.
Mix the yoghurt, ginger/garlic paste, red chilli paste, garam masala powder, and salt together.
Mix the chicken in marinade and leave for half an hour.
Roast the marinated chicken in a tandoor for approx. 15 minutes until it is 75% done.
Heat 100g of clarified butter in a heavy pan. Then put 1½ teaspoons of chopped garlic into the pan, and stir until sizzling.
Add one chopped onion, a teaspoon of chopped zinger, and keep stirring until golden brown. Then add two chopped tomatoes and cook them until they have slightly reduced.
Add the tandoori chicken and gravy into the pan, a teaspoon of garam masala powder, a small amount of red chilli powder, and some salt to taste. Stir all the ingredients together then cook it for another five minutes over a gentle heat to thicken the gravy.
Lastly, garnish with chopped coriander, a few slivers of ginger, and a dash of single cream and butter.