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