Let your butter sit at room temperature for about 30 minutes until it's soft enough to leave an indent when pressed but not greasy or melted. Cut the butter into chunks.

Place the softened butter in your mixing bowl and beat it on medium speed for about 2 minutes until it becomes pale and fluffy. Scrape down the sides of the bowl with your rubber spatula.

Add the sifted powdered sugar one cup at a time, mixing on low speed after each addition to prevent a sugar cloud. After adding all the sugar, the mixture will look dry and crumbly.

Pour in the vanilla extract and add the pinch of salt, then mix on low speed until combined.

Add 2 tablespoons of milk and beat on medium speed for about 2 minutes until the frosting becomes light and fluffy. If the frosting seems too thick, add the additional tablespoon of milk one teaspoon at a time until you reach your desired consistency.

Increase the mixer speed to medium-high and beat for another 2 to 3 minutes until the frosting is noticeably lighter in color and texture.

Test the frosting consistency by spreading a small amount on a cookie or the back of a spoon. Add more powdered sugar a tablespoon at a time to thicken, or more milk a teaspoon at a time to thin.

If you're tinting the frosting, add gel food coloring one drop at a time, mixing thoroughly between additions until you achieve your desired shade.

Use immediately to frost completely cooled cookies, or store covered in the refrigerator for up to two weeks.