I've been happily promoting the use of pollack over the years but I have noticed that in Lyme Bay recently, pollack haven't been quite so prolific – perhaps they are now being over-fished due to us chefs keeping on endorsing the stuff! I've recently started using coley in our restaurants and it's a bloody good alternative to both pollack and cod.
On the subject of sustainable fishing I would highly recommend watching The End of the Line (endoftheline.com), which is a must-watch film on the decline of the fish in global waters.
4 thick fillets of coley weighing about 200g each, skinned and boned
Sea salt and freshly ground black pepper
2 medium shallots, peeled, halved and finely chopped
200-250g oyster mushrooms, halved if large
200ml double cream
1tbsp chopped parsley
Lay the coley fillets on a tray and scatter them generously with sea salt, then leave for approximately 20 minutes. Meanwhile melt about one-third of the butter in a wide thick-bottomed pan and gently cook the shallots for 2-3 minutes until soft. Add the oyster mushrooms, cover with a lid and cook on a medium heat for 4-5 minutes, stirring every so often.
Add the double cream, season and simmer until the cream has reduced and is just coating the mushrooms. Add the parsley and remove from the heat.
Rinse the coley fillets under cold water and dry them on some kitchen paper. Heat the rest of the butter in a frying pan until foaming and cook the coley fillets, non-skin side down first, for 3-4 minutes on each side, giving them a nice golden colour.
Re-heat the mushrooms (add a little water if the sauce is a bit too thick) and spoon on to plates, drain the coley on some kitchen paper and place on top of the mushrooms.