In mixing bowl with paddle attachment cream together cream cheese and butter until well combined. Beat in vanilla and salt.
Gradually add powdered sugar beating at low speed. When all the sugar is added scrape down the sides and beat at medium high until light and fluffy, about 2 minutes.
Notes
This frosting is not just for carrot cake! So good on chocolate cake, too. Easily doubles if you are frosting a larger cake, this amount is perfect for Granny's Carrot Pineapple Cake.