Preheat the oven to 160°C and grease individual ramekins or a single ovenproof dish with extra butter.
Place the butter and caster sugar in a mixing bowl and using an electric whisk, beat until pale, light and creamy.
Add the eggs yolks, one at a time, mixing well after each addition.
Whisk in the milk, orange juice, lemon juice and zest.
Sift the flour over the mixture and mix until just combined.
In a spotlessly clean mixing bowl, whisk the egg whites until firm, but not stiff and then fold them gently into the batter.
Pour the batter into the ramekins or baking dish and stand in a baking tray. Half fill the baking tray, surrounding the dishes, with hot water to create a ‘water bath’ for the puddings.
Bake in the oven for 20-25 minutes, for ramekins or 40-45 minutes for a larger pudding, or until the top is lightly browned and set and there is a soft citrussy sauce underneath.
Allow to stand for 5 minutes before serving, topped with lemon zest and a dusting of icing sugar. Serve with whipped cream or ice cream, if desired.
15ml icing sugar
15ml finely grated lemon zest
Whipped cream or ice cream (optional)