In a large skillet, melt
butter over medium heat. Add chanterelles and shallots and
cook, stirring frequently, until moisture is evaporated, about 15 minutes. Whisk in
flour, then gradually blend in half-and-half and
wine. Stir in
tarragon,
salt and
pepper and
cook over moderate heat until thick, about 3 minutes. Stir about half cup hot mixture into
egg yolks, then return to pan and stir to blend.