Step 1:
Boil the vinegar, white wine, shallots and herbs, add salt and pepper,
over moderate heat until there are 3 tablespoons of sauce remaining,
for 10 to 15 minutes.
Step 2: Beat the egg
yolks. Mix with wine and vinegar mixture, beat. Add 1 tablespoon of
butter. Cook over low heat for 5 minutes max. Do not let the sauce boil.
Step 3: Melt 1/2 cup
of butter. Then add the melted butter to the mixture and beat. Add parsley
or tarragon and beat while cooking over low heat for 5 minutes max in
step 3.