dry white wine
very finely chopped shallot
ground black pepper, more if desired
finely chopped tarragon leaf
unsalted butter, very soft
( I've always used 1 1/2 sticks)
pepper, if desired
lemon juice, if desired
- Combine vinegar, wine, shallots, black pepper, and 1 1/2 teaspoons tarragon in a small saucepan.
- Cook over medium heat until reduced to 1 tablespoon, 5 to 10 minutes.
- Add egg yolks and 1 tablespoon of water to reduced vinegar mixture.
- Whisk until thick and pale, about 2 minutes.
- Set pan over moderately low heat and continue to whisk at reasonable speed reaching all over bottom and insides of pan, where eggs tend to overcook.
- To moderate heat, frequently move pan off burner for a few seconds, then back on.
- As they cook, the eggs will become frothy and increase in volume, then thicken.
- When the bottom of the pan is visible in the streaks left by the whisk and the eggs are thick and smooth, remove from heat.
- By spoonfuls, add soft butter, whisking constantly to incorporate each addition.
- As the emulsion forms, add butter in slightly larger amounts, always whisking until fully absorbed.
- Continue incorporating butter until sauce has thickened to consistency desired.
- Season with salt, remaining 1 1/2 teaspoons chopped tarragon and, if desired, pepper.
- Add a few droplets of lemon juice if necessary.