Prepare the Pan: Line an 8×8-inch baking pan with parchment paper, ensuring overhang on the sides.

Mix the Base Ingredients: Combine melted butter, 1 cup creamy peanut butter, graham cracker crumbs, and powdered sugar in a large mixing bowl. Mix until fully incorporated.

Press into the Pan: Pour the mixture into the prepared pan and press firmly into an even layer.

Melt the Chocolate Topping: Combine chocolate chips and ¼ cup creamy peanut butter in a microwave-safe bowl. Microwave in 20-second intervals, stirring until smooth.

Spread the Chocolate Layer: Pour the chocolate mixture over the base, spreading evenly to the edges.

Chill the Bars: Refrigerate for 1-2 hours until set.

Slice and Serve: Lift the bars from the pan using the parchment overhang and slice into squares or rectangles.