Crush the garlic cloves to a paste with a little salt in a pestle and mortar. Mix in the paprika, cumin, black pepper and half the olive oil.Toss with the chicken and leave for as long as you can.
Heat the remaining oil in a shallow casserole. Add the chicken pieces and cook, turning, until golden on all sides. Remove from the pan with a slotted spoon and set aside.
Add the onion to the pan and cook until golden, then add the saffron, turmeric and olives. Cook over a medium heat for 2 mins then return the chicken to the pan.
Pour over the juice of a lemon and 8 fl oz cold water. Slice the other lemon and add to the pan. Bring to the boil, cover and simmer for about 15 mins until the chicken is cooked, basting regularly.
You will need about 5 tbsp of the sauce per person, so if too much remains boil hard to reduce slightly. Check seasoning.
Serve with the sauce spooned over and couscous or rice.