Directions:With an electric mixer, beat butter for 1 - 2 minutes on the medium setting. Add 3 cups of the 3.5 cups of sifted powdered sugar to the mixer, gradually mixing it in with the lowest speed setting. Once thoroughly mixed, add the salt, vanilla and 2 tbsp. of the milk, again mixing thoroughly. While doing this, increase the setting to medium again, continuing to mix for 2 - 3 minutes. Judging by the texture of the frosting you can either add more of the powdered sugar if it is too runny, or more of the milk if it is too thick. If not, leave as is. Spread on sweet baked goods, such as cupcakes, cakes or even breakfast rolls. Store any extra in a mason jar in the refrigerator.