My mom makes these every year and give them out as gifts...soooo good!
1 cup butter
2 cups graham cracker crumbs
2 cups powdered sugar
1 cup smooth peanut butter
2 cups chocolate chips
Mix butter, graham cracker crumbs, powdered sugar, and peanut butter. (an easy way to measure the peanut butter is to put 1 cup of water into a measuring cup, and then add enough peanut butter to it that the water reaches 2 cups).
Press mixture into a 9x13" pan.
Melt chocolate chips in microwave and stir until smooth (try a minute first, and then check).
Spread chocolate carefully over peanut butter layer with a spatula. (Having one person to pour the chocolate and one to spread works well!).
Let the chocolate cool for a while, and then cut into bars before the chocolate is completely hardened (or else the chocolate layer will just crack).