Combine sugar, water, and corn syrup in heavy-bottomed saucepan.
Bring mixture to a bowl over medium heat. Cook, without stirring for 15-20 minutes or until a patch of golden colored sugar develops. (Golden - not golden brown.)
Swirl the sugar mixture around the pan until the entire mixture turns an even, golden color.
Turn off the heat and slowly stir in heavy cream and buttermilk being careful as the mixture will bubble slightly.
Stir in butter until fully combined.
Stir in bourbon or vanilla extract.
Let cool to room temperature and then transfer to an airtight container. Store in the refrigerator for up to a week.
If any clumps or crystals form, just heat the sauce again over low heat.