In a medium bowl, mix together the butter, graham cracker crumbs, confectioners' sugar, and 1 cup peanut butter until well blended. Press evenly into the bottom of an ungreased 9x13 inch pan.
In a metal bowl over simmering water, or in the microwave, melt the chocolate chips with the 4 tablespoons peanut butter, stirring occasionally until smooth. Spread over the prepared crust.
Refrigerate for at least one hour before cutting into squares of 8 rows by 4 rows.
Store, covered, in the refrigerator. Bars can be frozen up to 2 months. Thaw overnight in the refrigerator before serving.
Chocolate Peanut Butter Bars Recipe: https://whatscookingamerica.net/candy/chocpeanutbutterbars.htm