Heat the olive oil in a deep casserole dish and add the onion. Fry over a medium heat for about five minutes; when the onion starts turning golden, add the cloves, cinnamon, star anise, fennel seeds, chilli flakes and ginger. Cook the spices gently for a minute, being careful not to let them to burn.
Add the lamb shanks to the pan and brown them in the onions and spices, turning to brown all sides. Finally, add the dried limes and dates to the casserole dish with just enough warm water to cover the shanks (about 900ml). Increase the heat to bring the mixture to the boil, then cover with a lid and reduce the heat to medium-low. Allow the lamb to simmer for about two hours, or until it is tender to touch and practically falling off the bone.
Remove the casserole dish from the heat and allow to cool slightly. Gently remove the lamb shanks from the casserole dish with a slotted spoon and set aside. Strain the liquid in the casserole dish through a sieve, discarding the whole spices. Return the strained liquid to the casserole dish, add the pomegranate molasses and season to taste with salt. Place back over a medium heat to reduce the liquid to a sauce with the consistency of double cream.
Meanwhile, put the couscous and drained chickpeas into a bowl. Bring the stock to a boil and season with salt, then pour over the couscous. Cover the bowl with cling film and allow to stand for 15 minutes.
While the couscous is standing, heat half the olive oil in a frying pan over a medium-high heat and add the aubergine cubes. Fry for about five minutes, or until they have caramelised and softened. Fluff the couscous grains using a fork and drizzle with the remaining olive oil and the lemon juice. Mix the fried aubergine into the couscous together with the parsley.
Return the lamb shanks to the sauce and heat through gently. Serve with the couscous, garnished with the remaining pomegranate seeds, if you like.