In a medium sized bowl, mix together the melted butter, pretzel crumbs, powdered sugar and 1 cup of the peanut butter until combined
Transfer the mixture to an ungreased 9 x 13 baking dish. Spread the mixture evenly and press down to the bottom of the dishIn a microwave safe bowl combine the chocolate chips and 1/4 cup of peanut butter.
Microwave until the mixture becomes totally melted and smooth - heat in increments of 30 seconds, mixing each time, and be careful not to overcook and scorch the chocolate
Spread the mixture over the peanut butter and pretzel layer.Refrigerate for one hour or more and cut into squares and serve