01 - Line an 8-inch square baking pan with parchment paper, leaving some overhang for easy removal.
02 - In a medium saucepan over low heat, combine peanut butter and butter. Stir until melted and smooth.
03 - Remove from heat. Add powdered sugar, vanilla extract, and salt; mix until fully combined and creamy.
04 - Spread the peanut butter mixture evenly into the prepared pan, smoothing the top with a spatula.
05 - In a microwave-safe bowl, combine chocolate chips and 2 tablespoons butter. Microwave in 20-second intervals, stirring between each, until fully melted and smooth.
06 - Pour the melted chocolate over the peanut butter layer, spreading evenly.
07 - Refrigerate for at least 2 hours, or until fully set.
08 - Lift the fudge out of the pan using the parchment overhang. Cut into 16 squares. Serve chilled or at room temperature.