Place the softened butter in a mixing bowl.
Beat the butter on medium speed for about 2 minutes until creamy.
Gradually add the powdered sugar, one cup at a time, mixing well.
Add the heavy cream or milk, vanilla extract, and a pinch of salt.
Mix on low speed until combined, then increase to medium speed.
Beat the mixture for 3-5 minutes until light and fluffy.
If too thick, add more cream, one tablespoon at a time.
If too thin, add more powdered sugar until desired consistency is achieved.
Taste and adjust flavorings as desired.
Use immediately or store in an airtight container.