1. In medium bowl, combine peanut butter and butter with electric hand mixer until smooth. Gradually add sugars until well blended. Shape mixture into 1 inch balls. Place each ball between 2 pretzels and gently press together. Refrigerate 1 hour.
2. Melt chocolate morsels according to package directions. Dip each pretzel sandwich in chocolate to cover half.
3. Place on parchment paper-lined baking sheet and let stand 30 minutes or until chocolate sets.
Makes about 25 bites.