Prepare the Peanut Butter Filling:
In a medium-sized mixing bowl, use a stand or hand mixer to beat together the creamy peanut butter, softened salted butter, granulated sugar, and salt until fully combined.
Gradually add the powdered sugar and continue mixing on a low setting until you have a soft, dough-like consistency.
Form the Pretzel Bites:
Line a large sheet pan with parchment paper.
Scoop out ½ tablespoon of the peanut butter mixture and roll it into a ball.
Place the peanut butter ball between two mini pretzels, gently pressing them together to form a sandwich about ½ inch thick. Repeat with the remaining peanut butter mixture, making approximately 36 pretzel sandwiches.
Chill the Bites:
Arrange the pretzel sandwiches on the prepared sheet pan and place them in the freezer for 30 minutes to set. Alternatively, you can use the refrigerator for this step.
Dip in Chocolate:
Once the sandwiches have set, place the dark chocolate chips in a microwave-safe bowl. Microwave in 15-second increments, stirring between each interval, until the chocolate is fully melted (about 2-3 minutes total).
Dip each pretzel sandwich halfway into the melted chocolate, then place them back on the parchment-lined sheet pan. Sprinkle with sea salt if desired.
Set the Bites:
Return the sheet pan to the freezer for an additional 15 minutes to allow the chocolate to set.
Serve:
Serve the peanut butter pretzel bites immediately or store them in the refrigerator until ready to serve. They are best enjoyed chilled.