Preheat the oven to 180 degrees Celsius (355 Fahrenheit) and grease 6 individual ramekins with butter or 1 large casserole dish.
Sift the flour into a large bowl and add the brown sugar, orange zest and stir to combine.
In a jug combine the milk, egg and melted butter and mix to combine. Add to the flour mixture and stir until combined before dividing between the ramekins.
To make the sauce, combine the caster sugar and cornflour and sprinkle on top of the puddings. Combine the orange juice and boiling water and gently pour over the top of the puddings before placing in the oven. Bake for 20 to 25 minutes, or until the pudding is golden.
Serve with whipped cream or vanilla bean ice cream.