Line a 9x13-inch pan with parchment paper, allowing excess to hang over the sides.
Place half of the chocolate in a medium bowl and microwave on 50% power in 30-second increments, stirring after each, until completely melted. Pour the chocolate into an even layer in the prepared pan.
Gently place the pretzel sticks in an even layer on top of the melted chocolate. Place the pan in the refrigerator while you prepare the next layer.
Whisk together the melted butter and peanut butter, then whisk in the powdered sugar until completely smooth. Spread in an even layer over top of the pretzels.
Melt the remaining half of the chocolate using the same method as in step #2. Pour the melted chocolate over the peanut butter layer and use an offset spatula to spread in an even layer. Return to the pan to the refrigerator until set, about 30 minutes. Cut into bars and serve. Leftovers should be stored in an airtight container in the refrigerator for up to 2 weeks.