In a heavy saucepan, combine first four ingredients. Cook and stir over medium heat until sugar is dissolved. Bring to a rapid boil and cook until a candy thermometer reads 245° (firm-ball stage). Add cream and butter; heat and stir until mixture reaches 245° again. Pour into a greased 15-in. x 10-in. x 1-in. pan; cool. When cool enough to handle, roll into 1/2-in. logs or 1-in. balls. Wrap individually in foil or waxed paper; twist ends.