Begin with the Base: Start by placing the softened butter in a large mixing bowl. If you're using a stand mixer, fit it with the paddle attachment. Beat the butter on medium speed until it's creamy and lightened in color, about 2 minutes.

Incorporate the Sweetness: Gradually add the powdered sugar to the creamed butter. It's best to add about half a cup at a time, beating well after each addition. This method prevents the sugar from flying everywhere and helps it incorporate evenly into the butter.

Enhance the Flavor: Once all the sugar is mixed in, drizzle in the vanilla extract.

Adjust the Consistency: Check the consistency of your frosting after you've added the initial 2 tablespoons of milk or heavy cream. If it's too thick, add more liquid, one tablespoon at a time, until smooth. If you're planning to pipe the frosting, you might want it a bit stiffer, whereas a thinner consistency works better for spreading with a knife.