
In the bowl of a stand mixer fitted with the paddle attachment, beat the softened butter and sifted powdered sugar on low. Gradually increase to medium-high to prevent a sugar cloud.
Beat for 3 minutes until the mixture is pale, light, thick, but smooth. It may look dry or crumbly at first, but keep beating until it holds together.
Scrape down the bottom and sides of the bowl and paddle, then add the cream cheese and beat on medium-high for 1 minute until fluffy.
Add the vanilla and salt and beat for 30 seconds until fully incorporated. Scrape down the bowl again as needed.