The key to making a successful authentic sauce lies in the right temperatures. So make sure the various ingredients are at room temperature when you begin.

In other words, melt the butter well in advance and let it cool slightly.

The sauce can be made in 4 different ways:- Sous Vide- Heavy-bottomed pot- Over a water bath- In a stand mixer (that can heat).

This version is made in a heavy-bottomed pot.

Melt the butter in a pot over low heat and let it cool slightly.

Pour the cream into a bowl and whisk it into whipped cream.

Use a clean pot to whisk the egg yolks, salt, and lemon juice over low heat.

Whisk for longer and harder than you might think. When it thickens slightly, add the butter very slowly - while still whisking vigorously.

Continue to add the butter slowly and when all the butter is used, fold the whipped cream into the sauce.

The sauce should be served immediately.