01 - Line an 8x8 inch baking pan with parchment paper, allowing some overhang to assist with removal.
02 - In a large bowl, blend melted butter and 1 cup creamy peanut butter until smooth.
03 - Mix in powdered sugar, graham cracker crumbs, and vanilla extract. Stir until a cohesive, thick dough develops.
04 - Press the peanut butter mixture firmly and evenly into the prepared pan. Smooth the surface with a spatula.
05 - Combine chocolate chips and 1/4 cup creamy peanut butter in a microwave-safe bowl. Microwave in 30-second bursts, stirring between each, until fully melted and glossy.
06 - Evenly pour and spread the chocolate-peanut butter mixture over the base.
07 - Refrigerate for at least 2 hours or until the topping is set.
08 - Using the parchment overhang, lift the slab from the pan. Cut into 16 bars and serve.