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
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.