This is one of the simplest and most delicious fish dishes I know – another gem which Jane Grigson taught us when she came to teach at the Ballymaloe Cookery School in 1989.
Preheat the oven to 180°C/350°F/Gas 4. Lightly butter the ovenproof dish. Season the fish with salt and freshly ground pepper. Arrange the fillets in a single layer. Mix the grated cheese with the mustard and cream and spread carefully over the fish. s