Gather the ingredients - * Peanut butter * Butter * Powdered sugar * Vanilla extract
In a microwave safe bowl, microwave butter and peanut butter until the butter has melted.
Add in vanilla extract and powdered sugar, mixing until fully combined.
Transfer to a 8x8" pan lined with aluminum foil that is sprayed with nonstick spray or butter. Spread peanut butter mixture evenly into the pan before covering and transferring to the refrigerator to chill for at least 4 hours.
Cut into 1" square pieces before serving.