1) To make the masala paste, roughly chop the ginger, garlic and deseeded chilli. Blitz in a blender with the cumin, coriander, turmeric, paprika, garam masala and the seeds from the cardamon pods. Add a splash of water to bring the paste together. 2) To make the tikka masala, heat the oil and butter in a large saucepan over a low heat, then add the onions, cook for 15-20 mins until soft and golden. 4) Add the masala paste and peppers and fry for 5 minutes more. 5) Add the chicken, tomatoes, tomato purée and 200ml water, season to taste. Stir to mix well. 6) Bring to the boil then lower the heat and simmer for 15 - 20 mins, stirring occasionally, until the chicken is cooked. 7) Add the cream and yogurt, then gently warm through. 8) Serve with coriander leaves sprinkled to top and mango chutney.