1/4 c. tarragon vinegar
1/4 c. dry white wine
2 tbsp. finely chopped fresh tarragon or dried
1 tbsp. finely chopped onion
3 egg yolks
1/2 c. butter

In small saucepan combine vinegar, wine, and 1 tablespoons tarragon, and the onion. Bring to boil over medium heat. Reduce heat and simmer, uncovered until liquid is reduced to 1/4 cup 8-10 minutes.

Strain mixture into top of double boiler. Beat in egg yolks. Cook over hot, not boiling, water until mix thickens. Beat in butter, 1 tablespoon at a time. Stir in remaining tarragon. Serve at once, with steak.