Add the butter to the bowl of a stand mixer fitted with the paddle attachment and beat on medium-high until fluffy, about 30 seconds.
Scrape down the sides and add in the powdered sugar slowly with the speed on low. Gradually increase speed to medium-high after all the sugar is incorporated. Whip for about 1 minute until light and fluffy.
Turn speed down to medium and stream in the vanilla and heavy cream. Sprinkle in the salt. Turn the speed back up to medium-high and whip for another minute, until very light in color and texture.