Pre-heat your grill at the maximum temperature setting. Place all "marinade" ingredients into a bowl and mix together. Now, place the marinated chicken on a foil lined oven tray.
Grill chicken for 8-9 minutes until cooked (the chicken should be white all the way through). Remove from grill and keep aside.
Heat the ghee and oil in pan on a medium heat setting. Once hot add the cumin seeds. Then add the onions along with ½ tsp salt. Cook for 2-3 minutes until translucent.
Now add the garlic and ginger and mix. Continue to cook for a further 2-3 minutes until golden brown.
Add the chopped tomatoes and purée to the pan and stir. Place a lid on top and cook for 2-3 minutes allowing them to completely soften.
Reduce heat slightly and add the green chillies, coriander powder, paprika, turmeric, garam masala and the remaining salt and mix well. Cook for 2-3 minutes. When you see the oil begin to separate from the masala paste, add the grilled chicken along with the sliced peppers and water.
Mix well and place on a medium/high heat. Place a lid on the pan and cook for 5-6 minutes. Finish with roasted cumin powder a sprinkle of fresh coriander. Taste for salt and chilli and adjust accordingly. Remove from heat.