01 -  Preheat oven to 375°F. Line an 8x8-inch baking pan with parchment paper, extending the paper over the sides for easy removal. 
 02 -  In a large mixing bowl, whisk flour, baking powder, baking soda, and salt. Cut in cold butter with a pastry cutter or fork until mixture forms coarse crumbs. 
 03 -  Add cold buttermilk and beaten egg to the bowl and stir just until the dough begins to form. Avoid overmixing. 
 04 -  Transfer dough to a floured surface. Pat into a rectangle about 1/2-inch thick. Fold into thirds, rotate 90°, and fold again; this process enhances the layers. 
 05 -  Press or roll the dough into a rectangle that fits the prepared pan. Lay it evenly into the baking pan. 
 06 -  Brush the dough with melted butter. Combine sugar and cinnamon, then distribute evenly across the surface. 
 07 -  Lightly press the crushed pretzels into the cinnamon sugar layer to create a crunchy topping. 
 08 -  Whisk powdered sugar, maple syrup, bourbon, vanilla extract, and salt until the mixture is smooth. 
 09 -  Evenly drizzle half the glaze over the pretzel topping. 
 10 -  Bake for 28–32 minutes until golden and puffed. Allow to cool in the pan for 10 minutes; use parchment overhang to lift bars out. 
 11 -  Drizzle with remaining glaze. Let cool completely before slicing into bars to maintain structural integrity.