Preheat your oven to 325 degrees F. Spray three 8-inch pans with non-stick cooking spray, line the bottoms with parchment and spray again. Set aside.
Place the pretzel sticks in a food processor or blender and pulse until the pretzels are finely ground and resemble flour. When you remeasure, you should have about a cup.
In a medium-size bowl, combine the pretzel crumbs, all-purpose flour, baking powder, baking soda, and salt. Whisk until the ingredients are well-blended.
In the bowl of a stand mixer fitted the paddle attachment, beat the butter and sugars on medium speed until light and fluffy. Add the eggs, one at a time, beating well after each addition.
With the mixer on low speed, add 1/3 of the dry ingredients and mix until combined. Slowly add half of the buttermilk and mix until incorporated. Continue alternating the flour and buttermilk until it has all been incorporated. Scrape down the sides of the bowl and slowly mix for another 20-30 seconds.
Divide the batter evenly among your pans and bake for about 25 to 30 minutes. Cool 10 minutes on a wire rack before inverting onto cooling racks to cool completely.