Moroccan Lamb and Vegetable Couscous

Name: Moroccan Lamb and Vegetable Couscous
Ingredients: 4 1/2 tablespoons unsalted butter; 1 tablespoon extra-virgin olive oil; 1 large Spanish onion, thinly sliced; Large pinch of saffron threads; Water; 4 meaty lamb shanks (about 1 pound each); Salt and freshly ground black pepper; 1 tablespoon sweet paprika, plus more for dusting; 2 teaspoons ground cumin; Large pinch of cayenne pepper; 3 large plum tomatoes—peeled, seeded and quartered; 10 parsley sprigs and 1 large thyme sprig, tied in kitchen string; 3 medium boiling potatoes, cut into 1 1/2-inch chunks; 3 large celery ribs, cut into 2-inch lengths; 2 large carrots, cut into 2-inch lengths; 2 red bell peppers, cut into 2-inch pieces; 3 medium zucchini, cut into 2-inch pieces; 2 cups frozen peas; 2 cups couscous; 1/4 cup slivered mint leaves; Harissa, for serving