In a small saucepan, boil the bourbon, stirring occasionally. Reduce to simmer and allow it to reduce to about 1 - 2 ounces. Stir every couple minutes.
Remove it from the heat and stir in the salt.
Preheat oven to 170 or the lowest it will go. Lay out a piece of parchment paper on a sheet pan and spread the bourbon salt on it. Put in the oven and allow to dry out for about 60-90 minutes. Stir every 15-20 minutes or so.
Once the salt is dry and no longer showing any signs of moisture, store in an airtight container for up to 3 months.
Notes
Stove Top: Don't leave the stove while the bourbon is on. You need to stay near and keep stirring it every couple minutes. Oven Tip: Watch the salt while it is in the oven so it doesn't burn. Substitute: Whiskey, wine or other liquors in place of the bourbon.