Diana, Whakatane.

Place mashed potato in the bottom of a shallow Pyrex and place hake or cod fillets on top of mash after dipping first into melted butter. Bake until fish is cooked about 12-15 minutes at 180C. Mix together – half cup of mayo., half a cup of grated cheese, 2 egg yolks, a teaspoon of dried mustard, and stir in the whisked egg whites. Place over cooked fish and bake until nicely browned in a moderate oven.