Lightly grease a 9” x 9” glass pan with butter.
Combine powdered sugar, brown sugar, butter and milk in a saucepan and stir over a low heat until the sugars have dissolved.
Bring to a boil over medium heat, then slowly boil for 5 minutes stirring constantly.
Remove the saucepan from heat. Add peanut butter and vanilla. Stir until blended.
Pour the Peanut Butter Fudge into the glass pan. Let cool. Once the Peanut Butter Fudge pan has reached room temperature, you can move it to a refrigerator to finish cooling.
Allow the Peanut Butter Fudge to cool for at least four hours. Enjoy!