Beat the softened butter with an electric mixer on medium speed for 2 minutes until pale and loose.
Sift in the confectioners' sugar so no hard lumps remain in the bowl.
Add the honey, cinnamon and salt, then beat on low speed until the sugar disappears.
Increase to medium-high and whip for 2 minutes until the butter looks airy and holds soft ridges.
Spoon the butter into one small serving bowl and serve immediately, or refrigerate it covered for up to 5 days and soften it for 20 minutes before serving.