In a large bowl with a handheld mixer or stand mixer fitted with the paddle or whisk attachment, beat the softened cream cheese and butter, powdered sugar, vanilla and salt until fluffy, 2-3 minutes.
Spread frosting generously over warm cinnamon rolls and serve.
Video
Notes
You want your cream cheese and butter to be at room temperature, but not warm, which can create an overly soft texture. If your frosting is too soft, refrigerate to firm it up enough for spreading (~15 to 30 minutes should do it).