In a mixing bowl on medium speed, cream the butter until fluffy.
Add the powdered sugar, beat for 3 minutes.
Add the bourbon, 1 tablespoon at a time, along with the vanilla, mixing continually until well combined, about 3 - 5 minutes.
Scoop the hard sauce into a bowl.
Refrigerate for at least 3 hours to let the flavors mingle.
Bring to room temperature 20 minutes before serving.
Will keep for 1 week.
Serve.
