• Line an 8x8-inch baking pan with parchment paper, leaving a slight overhang for easy removal from the pan. Set it aside.
• In a medium-sized, microwave-safe mixing bowl, add the butter and peanut butter. Heat in the microwave for 60 seconds. Carefully remove the bowl from the microwave. Add the vanilla extract and stir until well combined.
• Slowly add the sifted powdered sugar, 1 cup at a time, stirring with a wooden spoon until all the powdered sugar is completely incorporated and there are no streaks or lumps of powdered sugar remaining.
• Pour the peanut butter fudge mixture into the prepared pan and, using a spatula, smooth it out into an even layer.
• Set it aside while you prepare the chocolate layer.

Chocolate Layer

• Using a medium-sized heat-safe bowl, add the chocolate chips, butter, and sweetened condensed milk.
• Heat in the microwave for 45 seconds. Stir, and continue heating in 15-second intervals and stirring until the mixture is smooth.
• Using a silicone or offset spatula, evenly spread the chocolate over the peanut butter fudge layer.
• Cover and refrigerate for 2 hours.
• Grab the overhanging parchment and remove the fudge from the pan.
• Slice the fudge into 1-inch x 1-inch squares.