I have modified the recipe slightly. Find the original recipe here.

Ingredients
500 gms or around 1 lb. skinless boneless chicken thighs, diced
1 tbsp. ginger/garlic paste
2 tsp. green chillies, finely chopped (no need to deseed)
2 tsp. ginger, finely chopped
3 tbsp. oil
1 tsp. turmeric powder
1 tsp. salt
1 tbsp. lemon juice
2 tbsp. Greek yoghurt
120 ml double cream
A few strands of saffron
½ tsp. shahi jeera (black cumin)
2 tbsp. chopped garlic
2 tbsp. coriander, finely chopped
1 tbsp. cream cheese
A small piece of natural lump charcoal and a tsp of ghee for smoking.

Instructions

Pour the oil into a deep bowl and add the ginger-garlic paste, salt, turmeric, chopped green chillies, ginger, lemon juice and saffron.
Add the chicken pieces and one half of the cream. Mix well. Rub this into the chicken to marinate while you prepare the second marinade.
Heat the ghee over a low flame and add the shahi jeera (black cumin) and let it splutter.
Let this cool to room temperature.
Pour this mixture over the chicken and then add the rest of the cream, the cream cheese, coriander and the yogurt.
Pour mixture in a container with a tight fitting glass lid. Make a small bowl with foil and put it on top of the mixture. Heat the charcoal piece over an open flame till red hot. Put it carefully in the foil bowl and add the tsp. of ghee. The charcoal will start smoking. Cover the container with the lid immediately.
Allow to marinate for 24 hours.

To cook the chicken, thread them onto skewers and grill over medium heat until cooked through. Alternately bake in an oven at 180c for 6-8 minutes or until cooked through. I used an indoor stovetop grill and it worked great!

Serve hot with sliced red onions, lemon wedges and mint cilantro chutney.