Step 1

Place the milk in a large heavy-based saucepan. Use a small sharp knife to split the vanilla bean lengthways without cutting all the way through, then scrape the seeds into the milk. Add the vanilla bean and heat, uncovered, over medium heat until the milk just comes to the boil. Remove from the heat, cover and set aside for 10 minutes to allow the vanilla to infuse. Strain the milk into a heatproof jug.

Step 2

Use a balloon whisk to whisk the egg yolks and sugar in a medium bowl until the mixture pales slightly in colour. Gradually add the milk, whisking constantly until combined. Pour into the saucepan and cook over medium-low heat, stirring constantly with a wooden spoon, for 20 minutes or until the custard thickens and coats the spoon.

Step 3

Serve warm or cover the surface with plastic wrap and serve at room temperature.