In a large bowl, combine butter, graham cracker crumbs, powdered sugar, and peanut butter until well blended. Press the mixture evenly into the bottom of an ungreased 9x13 inch pan. Place pan in refrigerator for 20 minutes.
Using a microwave set at 50% power, melt the chocolate chips with the peanut butter, stopping every 15-30 seconds to stir until smooth.
Remove pan from refrigerator and spread the chocolate mixture over the prepared crust. Refrigerate for at least one hour before cutting into squares.
Recipe by CHIC AND SUGAR at https://www.chicandsugar.com/2015/01/no-bake-peanut-butter-and-chocolate-pile-ups/