In a large bowl mix together peanut butter and 2 tablespoons of butter. Add both types of sugar and stir.
Roll the peanut butter mixture into 24 small balls. Place a pretzel on the top and bottom of each peanut butter ball so it creates a sandwich.
Refrigerate for about 1 hour.
Microwave the chocolate chips with 1 tablespoon of butter for 30 second intervals, stirring in between each time until the chocolate is melted and has a smooth consistency.
Dip each peanut butter pretzel sandwich halfway into the melted chocolate and return to the cookie sheet.
Refrigerate for 30 minutes to allow the sandwiches to set.