Sprinkle ½ teaspoon of the salt, 1 teaspoon of the cumin, ½ teaspoon of the coriander, ¼ teaspoon of the turmeric, ¼ teaspoon of the cayenne and some pepper on the chicken. Mix well and set aside for at least 1 hour.
Put the garlic and ginger into a blender or food processor. Add 125ml/4fl oz of the measured water and blend until fairly smooth.