Alana Williamson's Chocolate Peanut Butter Bars

I'm posting this for Wendy, and everyone else who wanted the recipe for these treats.

1 cup butter melted
2 cups graham cracker crumbs
2 cups confectioners' sugar
1 cup and 4 Tbsp peanut butter divided
1 1/2 cups chocolate chips

In a medium bowl, mix together the butter, graham cracker crumbs, sugar, and 1 cup peanut butter until well blended. Press evenly into bottom of an ungreased 9 x 13 pan. Microwave the chocolate chips with 4 Tbsp peanut butter on high for 1 minute. Stir. Continue microwaving and stirring every 30 seconds until smooth. Spread over prepared crust. Refrigerate for at least 1 hour before cutting.