Line a 9 X 9 pan with wax paper, allowing the paper to drape over the ends. Lightly spray the wax paper with cooking spray.

In a 1-quart saucepan, heat butter, heavy whipping cream, whiskey, vanilla, and 1/4 teaspoon kosher salt over medium-high heat to boiling, stirring frequently. Once the mixture begins to boil, remove from the heat and set aside.

In a 3-quart saucepan, mix together sugar, corn syrup, and water. Turn on medium-high heat and heat to boiling WITHOUT STIRRING. Boil until the sugar turns a warm golden brown.

When the sugar mixture is done, turn off the heat and slowly add the cream mixture to the sugar mixture, while stirring. The mixture is going to spurt and bubble like crazy, just be careful. Cook the mixture over medium-low heat for about 10 minutes, until the mixture registers 248 degrees F (firm ball stage) on a candy thermometer.

Pour caramel into prepared pan and cool for 10 minutes. After 10 minutes, sprinkle with up to 1 tablespoon kosher salt. Allow the caramel to cool completely.

Cut the caramels into squares and wrap individually in parchment or wax paper.