(or John Dory or Brill)
For 4

4x 200g (7oz,) Fillets Plaice
1kg (2 lbs) Mussels-in the shell
30g (1oz.) Butter
1 small Onion
1 Bunch fresh Fennel (or a bunch Parsley and 2 tablespoons Pernod)
30g (1oz.) Butter (softened)
30g (1oz.) Flour
2 Tablespoons Cream (optional)

First wash the mussels and cut off their beards.
(these are the little pieces of fibres that they use to cling on to rocks)

Chop the Onion finely and the fennel and put these into a lidded pan with the butter on a very low heat. ( or use chopped parsley and the Pernod)
Cook for a few minutes until the onion softens..

Tip in the mussels (discard any that have opened and don’t close when you tap them) and put on the lid and cook just until all the mussels are open.
Spoon out all the mussels into a bowl to cool but keep all the juices, herbs and onion in the pan.
Once you can handle the mussels take them from their shells.
Keep the mussels aside, discard the shells and pour any juices in the bowl back into the pan.
Use your fingers or a fork to mix together well the softened butter and the flour.
(this mixture is called Beurre Manie)

Put the pan with the mussel stock on to simmer gently and drop in the beurre manie a little at a time and whisk together. This should make a good thin sauce- add the cream now if using.

Put about one inch of water in a large frying pan and bring this to the boil.
Slip in the four fillets and bring back to a gentle simmer, poach for just about four minutes (they will keep hot in the water for another few minutes)

Tip the mussels into the sauce and bring back to a simmer.
Plate the fish on warm plates and spoon over the mussels and the sauce.

Serve with rice or potatoes.