Bring the milk to the boil with the bay leaf, a pinch of the nutmeg and
the mace. Place the fish in a casserole dish (Dutch oven) and pour over
the milk. Cover and cook in a preheated oven at 180°C/350°F/gas mark 4 for
30 minutes. Strain and reserve the cooking liquor. Remove the bones and
skin from the fish and flake the flesh.
Melt half the butter or margarine, stir in the flour and cook for 1
minute. Whisk in 300 ml/0.5 pt/1.25 cups of the milk and cook, stirring,
until the sauce thickens. Add the remaining nutmeg and season to taste.
Keep the sauce warm, stirring occasionally.
Stir the remaining butter or margarine and the oil into the fish, followed
by the cream, garlic and 45 ml/3 tbsp of the remaining milk and season
with salt and pepper. Transfer the mixture to a pie dish and cover with
the egg slices. Fold the cheeses into the sauce, pour it over the fish and
bake in a preheated oven at 220°C/425°F/gas mark 7 for about 5 minutes
until the top is golden brown.