Clean, wash and drain the chicken pieces. Rub with salt and lemon juice and keep aside for 15 minutes.
Mix together hung yoghurt, tandoori masala, chilli powder, salt and 1 tbs vegetable oil. Rub the chicken pieces well with this marinade and leave for 3 - 4 hrs in the fridge.
Roast the tandoori chicken in the centre of the oven preheated at 425º F for 20-25 mins. Remove and allow it to cool. If you can barbecue or grill the chicken pieces it is great. Alternatively you could also broil the chicken under the oven broiler for 5-6 minutes on each side.
Peel and dice the onion, cut the tomatoes into two halves, deseed, slit and deseed the green chillies too and keep them aside.
Now prepare the butter sauce. Take a cooking pot, set it on medium heat. Add 2 tbs butter and before it melts completely add the chopped garlic, sauté till it changes colour a bit and starts infusing its flavour into the butter. Now toss in the diced onions and the deseeded tomato halves into the pan. Sauté till the onions and tomatoes soften a bit. Remove from the pan, let it cool down, make a purée and set aside.
Add more butter (2 tbs) and a little oil (1 tsp)to the same pot and throw in the whole spices (cloves, green & black cardamoms, bay leaf, fennel seeds, whole black pepper corn) followed by ginger juliennes and split green chillies (optional). When you get a whiff of the aroma from the whole spices add the onion, garlic & tomato purée (from the previous step) to the pan, sauté well with the whole spices for 2 minutes then add 2 heaped tsps tomato paste and continue to sauté. Add 1/4 cup of water and mix well to form an aromatic butter gravy.
Now toss in the roasted chicken pieces with all its juices into the butter gravy, then pour in 1/2 a cup of the whipping cream. Mix well by turning over the roasted chicken pieces gently, cover with a lid and let the chicken cook in the butter sauce on low medium heat for 10 more minutes., till it is soft and juicy and the butter rises on top.
Taste and add some salt if required. As a finishing touch sprinkle a pinch of powdered jaggery or brown sugar. Take a tsp of Kasuri methi and rub it in the palm of your hand with your fingers to release the aroma and dust it in the pot. We add this in the final stage to make the sauce aromatic.
You could infuse a smoky barbecue flavour into the butter chicken by smoking it. Take a piece of charcoal, heat it on an open flame till it is red hot, then put it in small steel or a tin foil cup. (tin foil shaped into a cup to hold the burning charcoal). Place the tin foil cup in the centre of the chicken pieces, place the burning charcoal in it, then add a blob of butter or ghee to it. When it starts smoking, cover the pot with a lid and leave it to smoke for 5 mins. This gives a smoky barbecue flavour to the butter chicken.
Transfer to a serving dish, drizzle some more cream on top of the chicken, garnish with the ginger juliennes and serve hot with Naan or Basmati rice.