Make the cream cheese frosting. Combine the cream cheese, milk, and vanilla in a medium-large bowl and use a handheld electric mixer to beat on low until just combined. Gradually add the confectioners' sugar and salt and beat until smooth and fluffy.
Use on cinnamon rolls. Immediately use an offset spatula to spread a generous amount of the glaze (usually around a heaping 1 Tablespoon per cinnamon roll) over the top of each cinnamon roll when fresh from the oven. The residual heat will help melt and spread the frosting.
