Beat butter for 2 to 3 min with a mixer with the paddle attachment on medium speed.
Add 3 cups of powdered sugar and turn your mixer on the lowest speed until the sugar has been mixed in well with the butter.
Increase mixer speed to medium and add vanilla, salt, and 3 tablespoons of cream and beat for 3 minutes.
If your frosting needs a bit more stiff consistency, add remaining sugar. If your frosting is a little too stuff add remaining milk 1 tablespoons at a time.
Should be able to ice up to 24 cupcakes or two round cakes. Can be kept refrigerated for up to a week