Method

1. Preheat oven to 180°C / 350°F / Gas Mark 4
2. Put the garlic, ginger, lemon rind, parsley, mint and rosemary in a food processor. Switch on for a minute or two until everything is finely chopped
3. Switch on again and add the oil slowly until you have a bright green mixture
4. Set the mixture aside. If you don’t have a food processor, just finely chop everything with a knife
5. Place the joint in a roasting pan with the onion and water, put in the oven and allow 20 to 25 minutes per ½kg / 1lb
6. 30 minutes before the end of cooking time remove from the oven; spread the herby mixture over the joint. Return to the oven and finish cooking
7. Keep an eye on the water level and top it up if necessary
8. When the lamb is cooked remove from the pan and keep warm. Discard the onion and remove excess fat
9. Boil up the pan juices and reduce to a syrup, this will make a rich, tasty sauce. This will take 2 to 3 minutes
10. Season and serve