Rinse the lemon, then remove the pulp, keeping the skin. Put the pulp in a food processor with the garlic, ginger, pepper and saffron and blend. Gradually add the oil. Place the mixture in a large mixing bowl.
Add the chicken to the bowl and rub inside and out with the mixture. Cover and let stand overnight.
Place the chicken breast side down in a large casserole and add the marinating mixture. Add the water to the bowl the chicken marinated in and swish it around. Add the water to the casserole. Add the onion and coriander. Add salt to taste. Bring to the boil on the stove top, turn heat down, partially cover and simmer 30 minutes. Uncover, turn the chicken breast side up and simmer 15 minutes more.
Remove the chicken and set breast side up in a baking dish. Roughly chop the preserved lemon skin and add to the cooking liquid in the casserole. Add the olives. Cook the liquid down to 2 cups. Meanwhile, preheat the oven to 260 degrees C.
Brown the chicken in the oven, it should only take a few minutes. Serve with the cooking liquid on the side in a sauce boat.