Vanilla bean pastry cream

Put two cups of whole milk in a medium heavy-bottomed pot; a thin pot scorches the cream.

Split the vanilla bean, scrape out the seeds and add seeds and pod to the milk; bring to a simmer over medium heat without boiling over.

Separate six eggs, keeping the yolks; whisk the yolks with 135 g sugar until slightly thick and pale lemony.

Take the simmering milk off the heat and infuse 15 minutes (no wait needed for extract or paste).

Whisk in 37 g cornstarch until there are no lumps; the starch stabilises the yolk proteins.

Remove the vanilla pod; temper the yolks by drizzling in a quarter cup of the hot milk, then add the rest.

Pour back into the pot through a fine-mesh strainer, pushing the vanilla seeds through.

Cook over medium-high, whisking constantly with a narrow whisk into the corners, until it thickens and bubbles 'burp'; heating also destroys the yolks' amylase, which would thin the starch.

Whisk in a tablespoon of butter until melted; optionally cook a little longer for a firmer cream.

Push through a sieve with a spatula to catch any overcooked egg.

Cool to room temperature with plastic pressed onto the surface so no skin forms; chill (can be made 24 hours ahead).

Variation: for diplomat cream, whip heavy cream to stiff peaks and fold in about a cup for this batch.

Whisk the chilled, set cream briefly until smooth and pipeable.