Bearnese Sauce

1/3 cup white tarragon vinegar (plus 2 more tablespoons if you are using fresh tarragon)
1/3 cup dry white wine
4 crushed peppercorns
1 heaping tablespoon very finely chopped shallots
2 heaping tablespoons finely chopped leaves of chervil or parsley
6 sprigs fresh or 4 sprigs bottled tarragon (with 2 tablespoons liquid from bottle)
Ingredients for 1 recipe Hollandaise, omitting lemon juice or vinegar

Combine in a small heavy saucepan vinegar, wine, peppercorns, shallots, chevril or parsley, and tarragon with liquid or the extra tarragon vinegar. (Reserve the leaves from half of the stalks and put aside.) Cook over high heat until reduced to 1/3 cup or less. Strain through very fine sieve or cloth. Make Hollandaise Sauce using strained liquid instead of lemon juice or vinegar. Very finely chop and add remaining chevril or parsley and remaining tarragon.