Place chicken in a large pot with some salt. Add enough water to cover it. Bring to a boil, then turn the heart down and simmer for 25 - 30 minutes.
Add the oil and ghee to a large pot. Heat over a medium/high heat, then add the onions. Cook for 10 - 15 minutes or until a deep golden brown.
Stir in the garlic, ginger and green chilli and cook for a further minute.
Pour in the passata and add the cumin, coriander, turmeric, red chilli and ginger powder as well as the red chilli flakes and salt. Cook for 12 - 15 minutes.
Add the curry powder and garam masala and cook for a further 5 minutes.
Preheat the oven to Gas Mark 8, 230 degrees.
Add the masala to a large oven tray, with the chicken and 1 ladle of the stock from the chicken. Add the vegetables. Mix everything together using a wooden spoon.
Bake for 45 minutes - 1 hour.Enjoy served with roti or rice.