Cut the chicken into serving portions (a pair of breasts into 4–6 pieces each, whole legs into 2–3 pieces each). Put 4 tablespoons oil in a large, wide, non-stick pan (a large, non-stick frying pan is also quite suitable) and set over a medium–high heat. When hot, put in the bay leaves, cardamon pods, cinnamon stick, cloves and red chillies. Stir for a few seconds or until the bay leaves turn a few shades darker. Now put in the chicken pieces and brown well on both sides. Add the sultanas and stir for a few seconds. Add the yoghurt, 1 teaspoon salt, lots of freshly ground black pepper and the chilli powder. Stir and bring to a simmer. Cover well, turn the heat to low and simmer gently for 15 minutes.

While the chicken simmers, put the ginger into the container of a blender along with 3 tablespoons water and blend until you have a smooth paste. Add the green chillies and a generous fistful of green coriander and continue to blend, pushing down with a rubber spatula when necessary. Now add the lightly drained spinach. Blend very briefly this time. The spinach should have a coarse texture and should not be a fine purée. Empty this green sauce into a bowl. Add the mustard and ¼ teaspoon salt. Mix.

When the chicken has cooked for 15 minutes, remove the cover and add the green sauce. Stir to mix. Bring to a simmer, cover again and cook for about 10 minutes or until the chicken is tender. Turn the chicken pieces a few times during this period.