Place the softened butter in a large bowl and beat with a mixer until smooth.
Add in the vanilla extract and 1/3 of the powdered sugar and begin beating it in on low. (To avoid plumes of sugar clouds).
Continue adding the sugar until all incorporated, then beat on high until light and fluffy.
Notes
*Use unsalted butter, and note that yellow butters will affect frosting color. *Sift your sugar if it's very lumpy, I usually don't need to. *If your frosting is thick, add 1/2 teaspoon of milk at a time and beat it in until you get your desired texture.