Vanilla Custard

Pour the milk and cream into a heavy pan.

Scrape the vanilla seeds in and drop the split pod in after them.

Warm over medium heat for 4-5 minutes, until the surface trembles and steam comes off it steadily.

Take the pan off the heat before it boils.

Leave it to infuse for 15 minutes, which is where the flecks and most of the flavour come from.

Whisk the egg yolks, caster sugar and fine salt together in a large bowl for about a minute, until the mixture has paled to primrose and thickened enough to hold a brief trail from the whisk.

Start whisking the moment the sugar meets the yolks. Sugar left sitting on raw yolk draws the water out of it and sets it into hard yellow grains that never whisk smooth again.

Pour a ladleful of the hot milk into the yolks in a thin stream, whisking constantly.

That is tempering: bringing the yolks up to the temperature of the milk a little at a time, so they warm through instead of scrambling the instant they meet a pan of hot liquid.

Add two more ladlefuls the same way, until the bowl feels warm against the back of your hand.

Pour the tempered yolks back into the pan with the rest of the milk, whisking as they go in.

Set the pan over low heat.

Stir constantly with a wooden spoon or spatula, in a figure of eight that reaches into the corners of the pan, where custard catches first.

Cook for 6-10 minutes, until the custard thickens enough to coat the back of the spoon and a finger drawn across it leaves a clean line with nothing running back into it.

Take it off the heat at that line and no later. Egg yolk sets at around 82C/180F, and a custard pushed past that point curdles into fine grains in a thin liquid within seconds and with almost no warning.

Pour it straight through a fine sieve into a cold bowl and whisk hard if it does start to grain. Caught in the first few seconds it comes back very nearly smooth, and left to set into scrambled egg it does not come back at all.

Pour the finished custard through a sieve into a jug in any case, which takes out the pod and whatever has set against the base of the pan.

Treat it the way the soft scrambled eggs in this collection are treated: low heat, constant movement, and off the heat while it still looks a shade loose.

Discard the vanilla pod, or rinse and dry it and keep it in the sugar jar.

Serve warm, poured over the apple and blackberry crumble, which is the dish it exists for.

Pour it over a warm square of the dark chocolate brownies for the same reason.

Press cling film onto the surface if it is not going straight to the table, since a skin forms over cooling custard within a few minutes.

Refrigerate what is left and use it within two days. It sets firmer as it chills and loosens again over low heat, stirred.