Heat sugar in a stainless saucepan on medium heat, do not stir until sugar begins to melt.
Once sugar begins to melt, stir it until it has completely melted and begins to turn golden brown.
When sugar has started to turn caramel colored, remove pan from heat and immediately add butter and brown sugar and quickly stir together.
Once the butter and brown sugar are completely melded with the caramel (add gentle heat if needed to incorporate brown sugar), add the vanilla, corn syrup, cream and salt.
Stir together well.
The caramel will thicken as it cools.
If a thinner caramel is required, add water one tablespoon at a time until the desired thickness is reached; if a thicker caramel is needed, reduce the amount of corn syrup used.