Nutrition: Per serving
Fill a pan a third full with just-boiled water from the kettle and set over a low heat. Sit a heatproof bowl on top, ensuring the water isn’t touching the bottom of the bowl. Tip the egg yolks, mustard and white wine vinegar into the bowl, and whisk really well.
Put the melted butter in a jug and very slowly pour it into the egg yolk mixture, whisking all the time. Start very slowly, only adding a little more once the previous addition has been incorporated and fully emulsified. Keep slowly adding the butter until all of it has been incorporated and you have a smooth, emulsified sauce.
Remove the sauce from the heat and season with salt, black pepper and a little lemon juice. Serve with poached eggs or asparagus.
