Zest half an orange and half a lemon.

Blanch the zest in boiling water for 2 minutes, then drain and rinse with cold water.

Set the blanched zest aside for garnish.

Juice the oranges and lemon, then pour the juices into a small pan.

Bring the juice to a hard boil and reduce it to 3-4 tablespoons.

Pour the reduced juice into a large bowl and let it cool to room temperature.

Once cooled, add the vanilla sugar (or superfine sugar and vanilla extract), double cream, and brandy or Grand Marnier (if using).

Whisk the mixture until it softly holds its shape.

Divide the syllabub mixture evenly between four glass dessert bowls or glasses.

Decorate each serving with the blanched orange and lemon zest.

Chill the syllabub in the refrigerator for at least 10 minutes before serving.

Consume within 3 hours of preparing for optimal texture.