The key to this sauce is the sugar's color. You're looking for a large patch of golden-colored sugar (this usually develops in one section of the saucepan).
1 1/2 cups sugar
1 tablespoon light corn syrup
1/2 cup heavy cream
1/4 cup buttermilk
1 tablespoon butter
2 tablespoons bourbon
How to Make It
Pour sugar into a heavy 5-quart saucepan. Stir in 1/4 cup water and corn syrup. Bring mixture to a boil over medium heat; cook without stirring for 15 to 18 minutes, or until mixture turns golden. Reduce heat to low and swirl mixture around pan until it turns golden amber in color.
Slowly add cream and buttermilk, stirring constantly with a long wooden spoon (be careful, mixture will bubble up). Stir in butter. Remove from heat and stir in bourbon. If caramel begins to clump and harden, return to low heat and stir until smooth.
The bourbon gives the caramel a kick, but you can swap in vanilla extract if you prefer.