Masterclass Hollandaise sauce

Fill a large bowl with cold water. Put the vinegar, bay leaf, peppercorns and 3 tbsp water in a small pan, then simmer, uncovered, until reduced to about 2 tbsp. Immediately dip the pan base in the bowl of water, to cool it down and stop the mixture evaporating.

Put the egg yolks in a large bowl with 15g of the butter and a small pinch of salt. Beat together until well blended. Carefully strain the vinegar and herb reduction through a sieve into the egg mixture.

Put the bowl on top of a pan that's a quarter full of simmering water - make sure the bottom of the bowl doesn't touch the water. Whisk with a balloon whisk, or an electric handmixer, on a slow speed, for 3-4 minutes, until pale and beginning to thicken.

Do not allow the mixture to overheat or the eggs may scramble. If the sauce seems to be getting too hot, remove the bowl from the pan and add a few drops of cold water, then continue whisking.

Beat in the remaining butter, on a slow speed, a cube at a time. Beat well after each addition and allow it to emulsify - combine and thicken - before adding more.

When the sauce has a light, creamy consistency, remove from the heat and whisk for another minute. Stir through the lemon juice and season. Serve poured over the asparagus.

If the sauce starts to separate or 'split' - transfer it to a bowl using a spatula. Add a tiny amount of cold water, then whisk in the rest of the butter, a little at a time.

You can make the sauce faster in a food processor. Put the yolks and vinegar reduction in the processor. Melt the butter in a pan - it will separate and the solids will sink.

With the mixer running, slowly pour the liquid (but not the solids) over the yolks. If the sauce is too thick, thin it down with a little water. Add the lemon juice and season.

To make a bearnaise sauce, to go with steak - add shallot, chopped tarragon and cracked pepper.

Replace the lemon juice with orange juice to make a maltaise sauce - great with white fish and veg such as asparagus and broccoli.

Fold a little whipped cream into hollandaise right at the end, to transform it into a mousseline sauce - great with subtle tasting fish dishes. Adding the cream at the end makes it less likely to separate.