Instructions

• Line an 8"x8" pan with parchment paper or foil, leaving an overhang on two sides for easy lifting; set the pan aside.
• Measure and then sift 3½ cups powdered sugar into a large bowl; set the sifted sugar aside.
• Place a heavy-bottomed saucepan over medium heat. Add 1 cup unsalted butter, 1 cup creamy peanut butter, and ½ cup Reese’s peanut butter chips. Stir constantly until everything is melted and the mixture is completely smooth.
• Reduce the heat to low and stir in 1 tablespoon pure vanilla extract.
• Still over low heat, add the sifted powdered sugar and ½ teaspoon kosher salt to the pan. Use a spatula to stir and incorporate the sugar and salt until the mixture is completely smooth.
• If you see lumps or a grainy texture, vigorously whisk and press the mixture against the bottom of the pan with the spatula to work out the lumps until smooth.
• Stir in ¼ cup marshmallow creme until fully incorporated and the mixture is smooth.
• Immediately spread the fudge mixture evenly into the prepared 8"x8" pan and smooth the top with an offset spatula or the back of a spoon.
• Refrigerate the pan for 1½ to 2 hours, or until the fudge is firm.
• Use the parchment or foil overhang to lift the chilled fudge out of the pan and place it on a cutting board. Cut into desired pieces (the recipe author prefers small pieces and cuts the 8"x8" pan into 64 pieces—8 cuts in each direction).