Place the lamb into a large pan and pour over the stock. Bring the liquid to the boil, then reduce the heat until it is simmering and continue to simmer for one hour.
Add the chopped vegetables and continue to cook for a further hour. Remove from the heat, cover and set aside to cool overnight.
When you are ready to serve the stew, return the mixture to the boil and continue to boil for 15 minutes, or until completely heated through.
To serve, divide the cawl equally among four to six serving plates. Serve with crusty bread and Welsh cheese.