Melt butter and sugar
         and cook until caramel color.
   At
         this time stay close to it and wait until the  forming of a foam  on top of the caramel          .
  It looks like it is          burning and is burning in fact.
          At          this time add the half & half
         gradually  
    BE VERY CAREFULL
          Add the remaining  liquid and bring it back
         to the boil
  Then using
         the mixture yolks / sugar proceed like  the making of the crème Anglaise