Place the egg yolks and sugar in a bowl and whisk until pale. Pour the cream and vanilla into a medium saucepan and bring to a simmer. Temper the boiled cream into the egg yolk mixture, whisking constantly, and then pour back into the pan.
Add the champagne reduction and bring to 84°C (183°F) to cook the eggs. Hydrate the gelatine in iced water, squeeze out the excess water, and then st