In the bowl of a stand mixer or using a hand mixer, beat the butter, vanilla, and salt until smooth.
Sift the powdered sugar to make sure it’s completely lump-free.
Alternate adding a little powdered sugar, and a little cream until everything is incorporated.
Store your leftover cinnamon roll frosting in an airtight container in the refrigerator. I like to add a layer of plastic wrap to the top to keep it from crusting over. It will stay fresh for up to a week in the fridge.