- 1/4 cup dry white wine
- 1/4 cup white-wine vinegar
- 1 small shallot, chopped
- 2 tablespoons chopped fresh tarragon
- 3 large egg yolks
- 1/2 cup (1 stick) unsalted butter, cut into 8 pieces
- 1 teaspoon fresh lemon juice
- kosher salt and black pepper
- In a small saucepan, combine the wine, vinegar, shallot, and 1 tablespoon of the tarragon. Boil until the liquid is reduced to 2 tablespoons, 8 to 10 minutes.
- Strain the vinegar mixture through a fine-mesh sieve into a medium heatproof bowl. Whisk in the egg yolks.
- Set the bowl over (not in) a saucepan of simmering water and cook, whisking constantly, until the mixture has thickened to the consistency of mayonnaise, 3 to 4 minutes.
- One piece at a time, whisk in the butter until melted and smooth. Remove from heat and whisk in the lemon juice, the remaining tablespoon of tarragon, and ½ teaspoon each salt and pepper.