Butter and season a shallow tray, sprinkle with the finely chopped shallots and parsley and lay the prepared fillets in the tray in a single layer with 200 g sliced button mushrooms, the tomato concassee and tarragon.

Add the wine and stock to barely cover the fish, cover with a buttered piece of greaseproof paper and poach in the oven at 175°C for 10 minutes.

Remove the fillets and place in a serving dish, cover and keep warm.

Strain the cooking liquor into a shallow pan, adding the garnish to the fish. Add the veloute and cream and reduce to a coating consistency.

Add the sabayon and pass through a fine strainer.

Whisk in the butter a little at a time, away from the stove, add the brandy and season with salt and cayenne.

Coat the fish evenly with the sauce and glaze under a very hot salamander grill.