Put the puree and sugar in a saucepan.  Bring to a
   boil over medium high heat, stirring constantly.
   Remove from the heat, skim the foam from the top,
   discard, and add the pectin. Return to the heat and
   bring again to a hard boil for 2 minutes, stirring
   constantly. Remove from the heat and stir constantly
   for 5 minutes.