1. Put the smokies in a frying pan and just cover with boiling water. Simmer for 5 minutes.
2. Remove the smokies, making sure they are well drained.
3. Pour off the water from the pan and discard or save for fish stock.
4. Return the smokies to the pan, pour the cream over them and simmer gently for another 5 minutes.
5. Place the fish on a serving dish, pour the creamy sauce over and garnish with watercress.