01 - Line an 8x8-inch baking pan with parchment paper, leaving an overhang for easy removal.
02 - In a medium bowl, combine creamy peanut butter, sifted powdered sugar, melted butter, vanilla extract, and salt. Mix until smooth and well combined. Spread evenly in the prepared pan and smooth the top.
03 - In a microwave-safe bowl, combine chocolate chips, sweetened condensed milk, and butter. Microwave in 30-second increments, stirring between each, until melted and smooth, approximately 1 to 2 minutes total.
04 - Pour the melted chocolate mixture over the peanut butter layer and spread evenly to the edges.
05 - Refrigerate for at least 2 hours or until fully set.
06 - Remove from the pan using the parchment paper overhang and cut into 24 equal squares.