Martha Stewart'S Bearnaise Sauce - cooking recipe

Ingredients

2 tablespoons tarragon vinegar
2 tablespoons dry white wine
1/4 cup very finely chopped shallot
1/4 teaspoon ground black pepper, more if desired
1 tablespoon finely chopped tarragon leaf
3 large egg yolks
1 tablespoon water
1/2 - 3/4 cup unsalted butter, very soft (I've always used 1 1/2 sticks)
coarse salt
pepper, if desired
lemon juice, if desired

Preparation

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.