Slow-cooked harissa lamb

1.Preheat oven to 160°C/140°C fan-forced. Using kitchen string, tie lamb at 2cm intervals to secure. Using a large sharp knife, score top of lamb several times. Place lamb in a glass dish. Using hands, rub harissa all over lamb. Cover with plastic food wrap; chill for 30 minutes to marinate.

2.Heat half the oil in a large frying pan over moderate heat. Add lamb; cook for 3 minutes or until seared all over. Transfer lamb to a roasting pan; drizzle with 1 tablespoon of remaining oil. Bake for 3 hours 30 minutes or until very tender. Remove from oven. Cover with toil: rest for 15 minutes.

3.Meanwhile, place potato in a large microwave-safe bowl. Cover with plastic food wrap; microwave on High (100%) for 7-8 minutes or until tender. Cool. Place in a large bowl.

4.Juice 2 of the oranges. Whisk remaining oil, orange juice, mustard and garlic in a small bowl. Season with salt. Using a small knife. peel and segment remaining oranges; add to potato. Add carrot, watercress, coriander and mint. Drizzle with dressing; toss to combine. Carve lamb. Serve with salad and yoghurt.