Soles filets "bonne femme" style

Preheat the oven to 200 °C (390 °F).

Rinse, wipe, and chop the parsley leaves.
Peel, rinse, and slice mushrooms.
Peel and finely chop the shallot.

In a large baking dish (casserole), spread butter, shallot, parsley and mushrooms.
Add salt and pepper.
Give some small incisions to the fillets (on the side where the skin was) to prevent them from retracting.
Put the fillets in length, and season them slightly (salt / pepper).
Fold the nets in half on themselves, sides incised inside.

At the last moment :
Wet with the white wine and 4 cl of fish stock (the liquid should almost cover the fish).
Cover with baking paper (possibly buttered under) with a hole in the center (chimney to let vapor exit).
Bake in the oven for 6 to 8 minutes.

At the end of baking, remove the dish and, keeping the fillets and garnish under the paper, empty it of almost all the cooking liquid in a saucepan.
Keep the dish warm, and reduce the sauce by 1/3 in the pan.
Add the cream to the sauce and cook while whisking until sauce becomes thick.
Then add to the sauce the rest of the cooking liquid from the dish.

Top the fish with this sauce and put under the salamander grill (or oven grill, door open).
Beware, the sauce should not boil.

This is a classic of the famous French chef Escoffier (who prepared it also with turbot or brill). "Bonne femme" are family dishes poached and with mushrooms. If you replace the mushrooms with some tomatoes, you get "soles Dugléré" (another classic).
Try to get whole fish (and get them prepared). This way you can stay away from tropical fish (European species : solea solea), make sure it is fresh (a lot of mucus, and transparent) and make your own fish stock with the sole bones.
In France minimum legal catch size is 24 cm. You can add an egg yolk to the cream (before adding the cream) to get a richer sauce.