Preheat your oven to 350℉. Line a 15" x10" rimmed baking sheet with parchment paper or aluminum foil for easy cleanup.
Lay the pretzels in a single layer on the prepared cookie sheet, covering the entire bottom of the pan. Set aside.
Melt butter and sugar in a medium saucepan over medium heat. Stir continuously until the mixture reaches a rolling boil.
Carefully pour the hot caramel mixture over the top of your pretzels, spreading it evenly to coat all pieces.
Place the baking sheet in the oven and bake for 10-15 minutes.
While the pretzel toffee is baking, melt the Ghirardelli wafers according to the package instructions.
Remove the baking sheet from the oven and immediately pour the melted chocolate over the caramel-coated pretzels. Use an offset spatula to spread the chocolate evenly.
Sprinkle chopped walnuts or holiday sprinkles on top of the pretzels for extra crunch and festive flair.
Allow the bark to cool and set at room temperature for about 30 minutes. Once hardened, break it into bite-sized pieces.