Trout “au Gratin”

• 4 fresh trout, filleted
• ¼ pint dry white wine
• ¼ pint water<

Poach trout fillets in a court-bouillon made of equal parts dry white wine and water, and seasoned to taste with salt and freshly ground black pepper.

Transfer fillets to a well-buttered ovenproof dish and keep warm. Add 4 tablespoons butter, quartered mushrooms and half the prawns to