Line a baking sheet with parchment or a silicone baking mat. Set aside.
Place the dark chocolate into a microwave safe bowl and melt in the microwave in 30 second increments at high power stirring between each until melted.
Pour the melted chocolate into a tall drinking glass and place on a flat surface.
Dip a pretzel rod into the chocolate to coat 3/4 of the pretzel and allow the excess to drip off.
Place the chocolate dipped pretzel on the baking sheet and repeat with the remaining pretzels.
Melt the white chocolate, if using, in a microwave safe bowl. Heat in the microwave in 30 second increments at high power stirring between each until melted.
Place the piping bag in a glass (this is to hold it upright, hands free) and pour the white chocolate into the bag.
Snip off the end of the bag and drizzle the white chocolate over the pretzels in a zig zag pattern.
Decorate with sprinkles, nuts, candy, etc, if desired.
Allow the pretzels to set for 30-40 minutes at room temperature.
Transfer to individual bags or a zip top bag to store for up to 10 days at room temperature.
Notes
This recipe is easy to double or triple and makes a great gift idea or additional to a holiday cookie tray.