With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy – about 2 minutes. Add 4 and 1/2 cups confectioners’ sugar, the heavy cream, and vanilla extract. Beat on low speed for 30 seconds, then increase to medium-high speed and beat for 2 full minutes. Add up to 1/2 cup more confectioners’ sugar if frosting is too thin or another Tablespoon of cream if frosting is too thick. Add a pinch of salt if frosting is too sweet. (I add 1/8 teaspoon salt.)Use immediately or cover tightly and store for up to 1 week in the refrigerator or up to 3 months in the freezer. After freezing, thaw in the refrigerator then beat the frosting on medium speed for a few seconds so it’s creamy again. Adding a splash of heavy cream or milk will help thin the thawed frosting out again, if needed.