Mix room temperature butter until a whipped consistency. Slowly add 1 cup powdered sugar and mix to combine.
Add in salt, vanilla, and heavy cream. Slowly mix in remainder of powdered sugar.
Notice I leave a big margin for the amount of powdered sugar to use. This is because everyone tends to have a frosting consistency they prefer. I like mine a bit thicker, so I tend to add more. Some keep the crumb coat frosting thinner, and make the frosting used for decorating a little thicker. If you’re unsure, use around the 4 cup range.