Step 1
In the bowl of a stand mixer fitted with the paddle attachment beat cream cheese and butter on medium speed until smooth and well combined. Add the brown sugar, vanilla, and salt and beat at medium speed for 2 minutes. Scrape the bowl.
Step 2
Reduce the speed of the mixer to low and slowly add the powdered sugar. Mix well. Scrape the sides of the bowl. Increase the speed to medium and beat at medium speed for 2 minutes.
You can add 1 tablespoon of bourbon to the buttercream frosting for additional flavor.