Zest one orange and juice all three to obtain about 200 ml of juice. Set aside.

In a saucepan, whisk the egg yolks with the sugar until pale and creamy.

Add the cornstarch, then slowly pour in the orange juice while whisking to avoid lumps.

Cook over low heat, stirring constantly, until the mixture thickens.

Remove from heat and let it cool slightly.

Soak the gelatin in a bowl of cold water for 5 minutes until softened.

Stir it into the warm custard until fully dissolved.

Let the mixture cool to room temperature.

Whip the cold heavy cream until stiff peaks form. Set aside.

Beat the egg whites with a pinch of salt until stiff peaks form.

Gently fold the whipped cream into the cooled custard.

Then fold in the egg whites, lifting the mixture carefully to keep it light and airy.

Mix until smooth and well combined.

Spoon the orange mousse into serving glasses or a large bowl.

Refrigerate for at least 3 hours until set.

Before serving, garnish with orange zest, fresh segments, or a mint leaf.