cool completely.
to make the frosting, fit a stand mixer with the beater attachment or use a large bowl and an electric hand mixer. on medium speed, beat together the cream cheese and butter until smooth. turn the mixer to low and gradually add the powdered sugar. once all the powdered sugar has been added, increase the speed to medium and beat for another 30 seconds. add the vanilla and pinch salt; beat for another minute or so until smooth. add a little milk (a couple of teaspoons at a time) if the frosting seems too stiff to spread.
spread frosting onto completely cooled cake. cut into 12 pieces and serve. cover 