Start with the lamb shank. Season with pepper and salt.
Heat a few tablespoons of olive oil in a large pot that fits a couscoussier and brown the shank on both sides.
Peel the onions and cut them into large pieces. Peel the carrots, cut them in half crosswise, and then cut them into pieces about 5 cm long.
Make a cross-shaped incision in the tomatoes. Bring water to a boil. Dip the tomatoes in the boiling water for 10 seconds. Remove them from the water and shock them under ice-cold water. Peel them and cut them into wedges.
Add the onions to the shank and sauté briefly. Now also add the tomato pieces.
Peel the butternut squash. Cut it in half and remove the seeds. Cut the squash into slices and then into pieces about 1 to 2 cm. Peel the turnips and cut them into cubes.
Pour the chicken broth over the shank. Add the carrots, squash, and turnips.
Rinse the chickpeas and add them to the stew.
Add the ginger and saffron. Season with pepper and salt. Lower the heat.
Place the couscoussier on the stew pot. Cover with the lid and let simmer for at least 1 hour.
Let the couscous soak in the lukewarm water.
Make the harissa.
Put the soaked couscous in a large bowl and stir or fluff it up. Place the couscous in the couscoussier. Make some holes in the couscous so that the steam can escape and let it steam for another 10 minutes without a lid until the couscous is cooked.
Transfer the couscous to a large dish and fluff it up.
Spoon the vegetables and meat on top and serve. Garnish with flat-leaf parsley.