1. In top of a double boiler or a metal bowl set over a saucepan of simmering water melt chocolate, stirring until smooth, and stir in butter until it is incorporated. 2. In heavy saucepan heat cream over moderate heat until hot but do not boil. Add sugar and stir until dissolved. Add cream to chocolate by 1/2 cupfuls, stirring until cream is incorporated before adding next 1/2 cupful. 3. Serve fondue in a fondue pot over a very low flame, with accompaniments. Makes about 3 1/2 cups chocolate fondue, serving 6 to 8. NOTES : By Food Editor Sara Moulton Recipe by: Good Morning America