Line a 9x13-inch baking pan with parchment paper, leaving some overhang for easy removal.
In a large bowl, mix melted butter and peanut butter until smooth.
Add powdered sugar and mix until fully combined.
Gradually add graham cracker crumbs, mixing until a thick, uniform mixture forms.
Press the mixture evenly into the prepared pan to create the base layer.
In a microwave-safe bowl, melt the chocolate chips with peanut butter in 20–30 second intervals, stirring until smooth.
Pour the melted chocolate over the peanut butter layer and spread evenly.
Refrigerate for at least 2 hours or until fully set.
Lift out using parchment paper and slice into bars.