Place cold egg yolks, cold butter and cold lemon juice in a small heavy saucepan. Heat slowly over a low heat, stirring often with a whisk, especially as it thickens. Stir constantly adding salt and pepper and the tarragon when sauce reaches thickness you want.
If it becomes too thick, thin with a few drops of hot water. If sauce develops lumps from heating too quickly without stirring, beat briskly with wire whip and then strain out any remaining lumps.
Delicious on asparagus, broccoli, cauliflower, artichokes, chicken, steak and eggs benedict. For a different hollandaise, reduce butter to 4 tablespoons and add 1/4 cup sour cream.
