Serve with beef or fish, yield 1 1/2 cups (6 tbls per serving). Combine vinegar, wine, pepper, scallions and tarragon in saucepan. Cook over low heat until reduced to half, about 8 minutes.Strain mixture into top of double boiler. With wire wisk or rotary beater,beat in beaten egg yolks and salt. Cook over hot water until thickened.Beat in butter 1-tbl at a time. Stir over heat till creamy, about 1 minute. Serve hot over beef or fish fillets.