In a large bowl with a hand mixer, or use a stand mixer with the paddle attachment, add the butter, brown sugar, and peanut butter. Beat on medium-high speed until lighter in color and fluffy looking, about 1-2 minutes.
Use Creamy Peanut Butter:Creamy peanut butter is the best to use in this recipe.I know some may want to use crunchy peanut butter for the added crunch but don't do it as crunchy peanut butter is much thicker and drier than creamy.