Combine brown sugar, milk, and butter in a medium saucepan over medium-high heat. Cook while stirring frequently until the brown sugar and butter dissolve and the mixture comes to a boil.
Boil for 2 minutes, then remove from heat. Stir the peanut butter and vanilla extract into the mixture until smooth and well combined.
Add the powdered sugar to a large bowl, then pour the hot peanut butter mixture over it. Beat together with a hand mixer until combined and there are no lumps of powdered sugar remaining.
Transfer the fudge to the prepared pan, and let it set at room temperature for about 3 hours.
Allow it to cool completely before slicing it into squares.
You could add chopped peanuts or sprinkle them on top for some extra crunch! I haven't tested it this way, but I bet you could even use chunky peanut butter instead of creamy!
This rich and creamy Easy Peanut Butter Fudge is impossible to resist! It has that classic soft fudge texture and is the perfect treat for sharing any time of year, but we especially love it during the holiday season!
With its perfect balance of peanut butter flavor and sweetness, it is the best homemade fudge.