Pour half of the chocolate over the pretzel thins and let the chocolate set. If you're in a hurry, you can place the entire baking/cooling sheet in the fridge to make the chocolate set faster. Once the chocolate has set, flip the pretzels over and pour the remaining melted chocolate on the other half and let them set.
Once chilled, place about 2 tablespoons on butter on one pretzel thin and sandwich another pretzel on top. Put the entire Chocolate Covered Pretzel Cookie Butter Sandwich in the freezer for about 10 minutes before eating. Repeat the process with the remaining pretzels and cookie butter.