Line 9-inch square pan with parchment paper; spray with cooking spray.
In 1-quart saucepan, heat butter, whipping cream, whiskey, vanilla and salt to boiling, stirring frequently. Remove from heat; set aside.
In 3-quart saucepan, mix sugar, corn syrup and water. Heat to boiling over medium-high heat. DO NOT STIR. Boil until sugar turns a light golden amber color and candy thermometer reads 310°F.
When sugar mixture reaches 310°F, add cream mixture. Beating with whisk, cook until thermometer reads 248°F. Pour caramel into pan; cool 10 minutes. Sprinkle with sea salt; cool completely.
Cut into squares; wrap individually in parchment paper.