To marinate the chicken
In a bowl, mix the diced chicken, yoghurt, garlic, ginger and tandoori spice. Cover and marinate in the fridge for approx. 4 hrs.
To cook the chicken
Heat a little clarified butter in a non-stick frying pan, brown the chicken in batches for approx. 3 mins., remove and season with salt. Heat the remainder of the clarified butter. Sauté the onion, garlic, ginger and spices in the same pan for approx. 10 mins. Add the tomatoes and butter, season with salt, simmer for approx. 20 mins. Stir in the crème fraîche, return the chicken to the pan, simmer for a further 5 mins.