Serves 22 egg yolks (save the whites, they will freeze very well for months)
2 tablespoons of white wine or white wine vinegar
2 tablespoons of lemon juice
125g of butter melted
salt and pepper
1 teaspoon of dijon mustard
tarragon to taste, i like quite a bit, a tablespoon i suppose...
In a saucepan heat the wine and lemon juice over a high heat until its reduced to half the volume, i.e 2 tablespoons of liquid.
Pour the hot liquid over the egg yolks, add the mustard and seasoning and whisk to combine for a few minutes to make the sauce light. You will notice the colour of the egg yolks starting to change to a lighter yellow as you whisk.
Now continuing to whisk pour in the melted butter in a slow steady stream until its all combined.
You will notice there will be a solid white matter at the bottom of the container which you had the melted butter in, DONT put this into the sauce, stop before it tips in, this is the fats from the butter which seperate during melting.
Stir in the tarragon, taste for seasoning, add more tarragon if you like, and serve either in a put on the side of the plate or poured over the steaks/fish