Melt the butter, brown sugar, corn syrup over medium heat and bring to a boil, stirring continuously.
Reduce heat and let boil for 3 to 4 minutes until thickened. Add the vanilla and salt while simmering.
Allow the sauce to cool to a warm temperature. Add cream until desired consistency is reached. As the caramel cools, it will thicken more. Keep that in mind when adding the cream.