1. Place a casserole dish with 30ml olive oil over a medium-high heat. Sprinkle the chicken thighs with 1 teaspoon salt and sear in the hot oil in two batches (adding a bit more oil for second batch,if necessary) to brown the skin – about seven minutes. Remove chicken and set aside. Discard all oil and wipe out pan.
2. Using a mortar and pestle (or a blender),crush the garlic,ginger,pepper,cumin,paprika,parsley,coriander and ½ teaspoon salt into a paste with the three tablespoons extra virgin olive oil and saffron water.
3. Place remaining 30ml olive oil in the casserole dish over a medium heat. Add the sliced onion and spice paste and cook gently,stirring regularly,for 5-10 minutes,until onion becomes translucent. Stir in the chicken thighs so that they are coated in the spice mix. Continue stirring while slowly adding the boiling water (or chicken stock). Reduce the heat to a gentle simmer,cover the casserole and cook for 30 minutes.
4. Add the olives,cover and cook for a further 10 minutes,then stir in the lemon juice. Remove from heat and rest,uncovered,for five minutes. At this stage,you can remove the chicken and reduce the sauce if it's a little too watery.
5. Place chicken on plates,spoon over olives and sauce,garnish with coriander and serve.