Bernaise Sauce
Source: James Beard American Cookery

1/2 cup white wine
1 Tbsp. finely chopped shallots or scallions
1 or 2 tsp. chopped fresh tarragon
3 or 4 egg yolks
1/2 tsp. salt
1/2 cup butter

Combine wine, shallots and tarragon. Cook until it is reduced to a mere glaze. Combine the glaze with the eggs and salt in blender or food processor. Heat butter till bubbling hot. Pulse processor to mix ingredients and then turn on again and gradually pour in melted butter in steady stream until sauce thickens. Additional chopped tarragon and parsley may be added.