Start off by making up the paste: crush the garlic and the salt with a pestle and mortar, then mix the garlic paste with the ginger and cinnamon and add the olive oil, whisking gently to get everything well combined.
Next put the chopped onions in a bowl, add a teaspoonful of the paste and toss them around in it so they are well coated. Now arrange the onions in the middle of the pre-heated roasting tin, return it to the oven and let them cook for five minutes.
Meanwhile make a couple of slits in each thigh with a sharp knife, then rub the rest of the spiced paste all over each thigh. After the five minutes is up, arrange the chicken thighs on top of the onion in the roasting tin, and return to the oven for a further 25 minutes. Chop each preserved lemon in half, and then each half into three, and when the 25 minutes is up, add them to the roasting tin along with the olives.
Finally pour in the white wine and season with salt and pepper. Return to the oven for another 30 minutes. Serve with rice or couscous and perhaps a green salad.