Mix peanut butter, melted butter and powdered sugar in a large bowl.

Stir in crushed graham crackers.

Spread peanut butter mixture in a 9 x 13 pan.

Melt chocolate chips, stirring frequently to ensure the chocolate doesn't burn. (This can be done using a double boiler over low heat, or using a microwave on medium power, stirring every 30 seconds until melted)

Spread melted chocolate over peanut butter mixture.

Refrigerate until chocolate is hardened.

Cut into squares, serve and enjoy!