Leave the tea to soak in the water for 10 minutes.
Heat the milk until very hot but do not boil. Leave it to infuse with the vanilla bean and the seeds for 10 minutes. Beat the egg yolks with the caster sugar until white and foamy. Strain the milk mixture into it and stir well. Also add the steeped tea. Return the mixture to the pan and stir over low heat until thicker, like a crème ang