Chocolate Peanut Butter Squares

Grease a 9x13 baking pan with butter and set aside. Melt one stick of butter in large saucepan over medium heat. Add entire jar of peanut butter and stir until melted. Gradually add powdered sugar and stir until melted or combined well. Remove from heat and add graham cracker crumbs. Use a potato masher to work crumbs into peanut butter mixture until smooth. If necessary, use your hands to knead the mixture. Firmly press the mixture into the greased baking pan and smooth it out until as flat as possible. Melt the second stick of butter in a small saucepan over medium heat. Add the chocolate chips and stir until melted. Pour the chocolate mixture over the peanut butter mixture and spread evenly over entire pan. Place the pan in the refrigerator for 45 minutes to an hour (but not too long) to allow the chocolate to set. Once the chocolate is set, remove from refrigerator and cut into slices but do not remove from pan. Put the pan back in the refrigerator and allow it to continue to set for a few hours. Once the bars are completely set, remove from pan. Store in a cool place.