Split the vanilla pod lengthways and chop into small pieces.
Pour the cream into a saucepan and add the vanilla pieces.
Bring to boiling point, then lower the heat and simmer for 5 minutes.
Beat the sugar and egg yolks in a large heatproof bowl until pale and creamy
Bring the cream back to boiling point and slowly pour over the egg mixture, whisking all the time until thickened.
6 servings