Reese's Bars

1 c Melted butter
2 3/4 c Icing sugar
1 c Peanut butter
2 1/2 c Graham wafer crumbs
12 oz Chocolate chips
Mix together first four and press into an ungreased 9 x 13 pan. Melt the chocolate chips and pour over the peanut butter mixture. Let cool slightly and then cut into bars before the chocolate hardens completely.