1. Place stock ingredients and 2 litres of water in a heavy saucepan,just large enough to fit the lamb shoulder,and bring to the boil. Add the lamb then reduce heat to a simmer,partially cover with a lid to slow evaporation,and braise the lamb slowly for 2 hours,until soft and falling apart.
2. Remove from the heat and leave to cool to room temperature in the braising liquid,then transfer to a refrigerator. When the stock is cold,remove solidified fat from the surface and discard,then take the lamb out of the stock,shred the meat and refrigerate.
3. For the dressing,combine all the ingredients in a bowl.
4. Remove lamb from the fridge and warm gently in a saucepan with the stock that is clinging to it.
5. To serve,place the shredded lamb on a serving plate and pour the dressing over the top,then top with extra chillies,if desired.
Serve with Neil's chicken and udon noddle salad as part of a lazy weekend lunch.