Place sugar, corn syrup, and bourbon in a large saucepan (be sure to use a large pot with high sides). Bring to a boil, boil, without stirring for 9 minutes or until light golden. Add the heavy cream, butter, vanilla, and salt, slowly stirring into pan. Boil until candy thermometer reaches 235 degree F, stirring frequently. This took me a total of about 25 minutes.