To make the ras el hanout, lightly bash the cardamom pods in a pestle and mortar, shake out the seeds and discard the pods. Bash and muddle in the remaining ingredients to form a powder.
Massage the ras el hanout into the lamb shanks, then place in a large ovenproof pan over a medium-high heat with a splash of olive oil. Cook for 6 to 8 minutes, or until browned all over, turning halfway. Meanwhile, prick and add the chilli to the pan and cook until slightly scalded all over, then remove to a plate with the lamb.
Peel and finely slice the garlic. Peel, halve and cut the onion into eight wedges. Peel and core the quince, then cut into eight wedges, too. Peel and chop the carrots at an angle into 4cm chunks. Trim and quarter the bulb of fennel.
Wipe the pan clean with a ball of kitchen paper, then place on a medium heat. Add a splash of olive oil, the pricked chilli and the bay leaves. Put the garlic and vegetables into the pan, then cook for 10 to 12 minutes, or until softened.
Add the saffron to a cup with a splash of boiling water, then leave for a minute. Return the shanks to the softened vegetables. Quarter and add the tomatoes along with the saffron mixture, whole preserved lemon and stock. Bring to the boil.
Cut out a circle of greaseproof paper to the size of the pan, scrunch it up under cold running water, then lay it out flat and place in the pan. Cover with a lid and place in the hot oven for 2 hours to 2 hours 30 minutes, or until the shanks are soft, delicious and the sauce has reduced.
Use a spoon to skim away any excess fat from the surface. Carefully remove the shanks to a plate, then place the pan over a medium-high heat for 5 to 10 minutes, or until thickened and reduced, stirring occasionally.
Place the couscous and half the mint sprigs in a bowl, cover with boiling water, pop a plate on top and leave to soak and infuse.
To make the salad, destone and roughly tear the olives. Pick the parsley and remaining mint leaves, then place everything in a bowl, squeeze over the lemon and orange juice, and add a drizzle of extra virgin olive oil and a pinch of sea salt and black pepper. Toss together and set aside.
Combine the rosewater and harissa, then swirl it through the yoghurt. Return the lamb shanks to the sauce. Fluff up the couscous, discarding the mint, then divide between your plates. Top with the tagine, scatter over the herb and olive salad, then serve with a dollop of the harissa yoghurt.