Add softened unsalted butter (¼ cup, i.e. ½ stick), powdered sugar (2 cups), vanilla extract (2 teaspoons), and a pinch of salt to a medium-sized bowl.
Use a hand or stand mixer to mix until combined (about 30-60 seconds).
Add milk one tablespoon at a time (2-4 tablespoons) until it's the consistency you desire.
Pour over slightly cooled cinnamon rolls and enjoy!
