Ingredients

Method

In a small saucepan, combine the white wine vinegar, white wine, half of the tarragon, shallots, salt, and pepper. Simmer over medium heat until the mixture is reduced to 2 tablespoons. Strain and set aside to cool.

Either:

In a heatproof bowl, whisk the egg yolks with the reduced vinegar mixture.

Place the bowl over a pan of simmering water, ensuring that the bowl does not touch the water. Whisk continuously until the egg mixture has thickened.

Gradually add the melted butter, whisking constantly, until the sauce is thick and creamy.

Remove from the heat and stir in the remaining chopped tarragon.

Or:

Whisk the egg yolks with the reduced vinegar mixture in a food processor until the eggs are creamy.

Trickle in the melted butter with the food processor running constantly. Only a very small amount at first to ensure that the mixture does not split.

When the butter has been added and the sauce has thickened, switch off the food processor, remove the mixture and stir in the remaining tarragon.

Finally:

Taste and adjust seasoning if necessary, then serve immediately.