Prep Time: 5 minutes
Cook Time: 15 minutes
Servings:
Finely chop the shallot and the herb stems, and place them in a saucepan. Chop the herb leaves as well, but set them aside in a bowl for later.
Pour the vinegar over the onion and stems in the saucepan and bring to a strong boil. Add the water, remove from the heat, and let stand.
Melt the butter in a saucepan until very hot. Ideally, use a kitchen thermometer and remove the pan from the heat once the butter reaches 100°C (212°F).
Carefully pour the clarified butter into a jug, leaving the sediment at the bottom of the pan. The butter should still be very hot.
Strain the vinegar reduction into a mixing jug. Add the egg yolks and salt, and blend together with the reduction.
Slowly and carefully pour in the hot clarified butter in a thin stream while blending constantly. Keep blending without interruption until the sauce is thick and smooth.
Taste and adjust seasoning with more salt if needed. Stir in the chopped tarragon and parsley. Done!