In a medium bowl, combine melted butter, graham cracker crumbs, powdered sugar, and peanut butter. Stir with a spoon until well mixed. Turn out into an ungreased 7x5-inch dish and smooth out. Place in the freezer for 5 minutes.
In a small, microwave-safe bowl, combine chocolate and peanut butter. Microwave for 30 seconds and stir. If necessary, microwave for an additional 15 seconds and stir, repeating until chocolate is melted and smooth.
Pour mixture over the cooled peanut butter and spread. Refrigerate for at least one hour before cutting. Enjoy!