Butter a soufflé mold generously and sprinkle the sides with caster sugar, tapping out the excess.
Preheat the oven to 200°C (th. 6).
Wash and dry the orange, then zest it finely to infuse the flavor.
Sweeten the milk in a saucepan. Reserve 1/2 cup cold milk and bring the rest to a boil.
In a bowl, dissolve the rice cream (or starch) in the cold milk. Gradually whisk into the boiling milk, stirring constantly until the mixture thickens immediately.
Remove from heat, incorporate the butter and egg yolks, stir well, and allow to cool.
Just before baking, fold in the liqueur and stiffly beaten egg whites gently, ensuring the whites retain their volume by folding lightly over them.
Fill the mold two-thirds full and bake for 30 minutes. Avoid opening the oven for the first 20 minutes to let it rise dramatically and burst beautifully.
Dust with icing sugar before serving for an elegant finish.
Source: Les Bons Desserts by Claude Mignières. A timeless French classic perfected over generations.
