01 -
In a large bowl, mix the melted butter, graham cracker crumbs, powdered sugar, and 1 cup of peanut butter until well combined.
02 -
Spread the mixture evenly into the base of a non-greased 9x13-inch dish (or 9x9-inch dish for thicker bars).
03 -
In a microwave-safe bowl, melt the chocolate chips with the remaining 4 tablespoons of peanut butter. Heat in 30-second intervals, stirring each time, until smooth.
04 -
Pour the melted chocolate mixture evenly over the peanut butter base.
05 -
Refrigerate for at least 1 hour, or until firm, before slicing into squares.