Pour wine and water into saucepan; cover.Simmer for 30 minutes. Do
not boil. Saute bread cubes in butter; add lemon rind. Cook over
medium heat until crisp and golden brown. Beat egg yolks till foamy;
add sugar. Beat until well blended.Stir in 1/4 cup wine mixture.
Return to remaining wine mixture, gradually, stirring constantly.
Cook for 1 minute; do not boil. Place bread cubes in soup bowls; pour
hot wine soup over bread cubes. MM Wrenn
Source:Military Officers' Wives:Holiday Cookbook
