Rinse the haddock, remove the fins and tail and cut up into large pieces. Place in a saucepan with the bay leaf, parsley stalks and slice of lemon. Add the water and bring up to the boil. Simmer gently, covered with a lid, for about 15 minutes, then strain off the liquor and reserve it. When the fish is cool enough to handle, remove the skin and bones and flake the flesh.
Melt the butt