To make classic vanilla buttercream frosting you will need: powdered sugar, butter, salt, vanilla, and milk.
Whip the Butter
Add the softened butter to a stand mixer and whip for 1-2 minutes with a whisk attachment.
Mix the vanilla extract with the whipped butter.
Add 2 cups of powdered sugar and a pinch of salt. Whip for 1-2 minutes. Add the remaining powdered sugar and whip again.
If the frosting is too thick, add milk or heavy cream, one tablespoon at a time. Then beat for another 1-2 minutes.
Check the Consistency
The frosting should hold its shape, but not be too firm.
Serve this buttercream with your favorite cakes, cupcakes, or cookies!