Recipe: Citrus Delight

Preheat the oven to 355°F (180°C) (gas mark 6). Butter a baking dish with a capacity of 1.3 qt (1.25 liters). Cream the butter, sugar and zests with an electric mixer until the mixture turns pale.
Add the egg yolks one by one, beating well after each addition. Pour in the citrus juice, milk, and flour. Whisk the preparation.
Beat the egg whites until stiff peaks form, then gently fold them into the batter. Pour the preparation into the baking dish.
Place this dish in a larger pan and pour boiling water up to halfway up the mold.
Bake for 40 to 45 minutes in the oven (cover with aluminum foil if the surface browns too quickly). Serve warm or cold with or without ice cream.