Cook the potatoes in boiling water for 20 minutes. Drain, add half the butter and mash. Season to taste, beat in the egg and set aside.

Place the fish fillets, milk, onion, carrot and bay leaf in a saucepan. Season lightly, bring to a boil, reduce heat, cover and simmer for 15 minutes. Then remove the pan from the heat and discard the onion and bay leaf. Strain the liquid and place fish, peas and carrots in a baking dish. Reserve.

Heat oven to 400 degrees Melt half the remaining butter in a saucepan and stir in flour. Cook for one minute. Remove pan from heat and stir in the strained milk - a whisk helps. Cook over medium heat until the sauce thickens. Stir in the nutmeg and cream. Check seasonings and pour sauce over fish and vegetables. Mix gently and sprinkle on the parsley.

Spread the potatoes over the filling and top with butter. Bake for ten to fifteen minutes until topping browns.

Note: Make this in individual dishes if you like. They do not freeze, but will keep in the refrigerator for three or four hours before brought up to heat in the oven.