- 40ml white wine vinegar
- 40ml water
- 1 small shallot, chopped
- A few sprigs tarragon
- 1 bay leaf
- 5 peppercorns
- 3 small egg yolks
- 150 g melted ghee
- Salt and freshly ground white pepper
- Place the vinegar, water, shallot, herbs and peppercorns in a saucepan and reduce the liquid by boiling for a few minutes until there is no more than a dessertspoonful.
- Strain through a sieve and leave to cool.
- Put the egg yolks into a small bowl (or double boiler if you have one) with half of the vinegar reduction and whisk over a pan of gently simmering water until the mixture begins to thicken and become frothy.
- Slowly trickle in the butter, whisking continuously – an electric hand whisk will help. If the butter is added too quickly the sauce will separate.
- When you have added two-thirds of the butter, taste the sauce and add a little more, or all, of the remaining vinegar reduction.
- Then add the rest of the butter.
- The sauce should not be too vinegary, but the vinegar should just cut the oiliness of the butter.
- Season with salt and pepper, cover with foil and leave in a warm, not hot, place until needed.