500ml full cream milk
1 tsp vanilla bean paste
6 large egg yolks
135g castor sugar
35g corn flour
50g butter, cold
Add the milk and vanilla bean paste to a medium saucepan, place over medium heat and bring to a boil. Remove from the heat.
In a bowl, whisk the egg yolks and sugar until light and fluffy. Add the corn flour and whisk vigorously until no lumps remain.
Whisk in 1/2 cup of the hot milk mixture until incorporated. Whisk in the remaining hot milk mixture.
Pour the mixture through a sieve back into the saucepan. Cook over medium-high heat, and whisk until thickened.
Remove from the heat and stir in the butter. Allow to cool slightly.
Cover with cling wrap, lightly pressing the plastic against the surface to prevent a skin from forming.
Chill for at least 2 hours or until ready to serve. The custard can be made up to 24 hours in advance.