1.Preheat oven to 125°C/250°F.
2.Blend or process herbs, garlic, salt, pepper and oil until combined.
3.Rub herb mixture all over lamb; place lamb in 2-litre (8-cup) flameproof dish. Bring stock, vinegar and mustard to the boil in small saucepan; pour mixture around lamb, cover. Cook, in oven, 4 hours.
4.Uncover lamb; cook, in oven, 1 hour.
5.Meanwhile, make burghul salad. Heat oil in medium saucepan; cook onion, stirring, until soft, stir in burghul. Add stock; bring to the boil, season. Cover; cook, over low heat, about 10 minutes or until liquid is absorbed. Transfer to medium bowl; fluff with fork, cool. Stir in remaining ingredients; season to taste.
6.Serve lamb and pan juices with burghul salad; sprinkle with nuts.