01 - Preheat the oven to 450°F. Line a baking sheet with parchment paper.
02 - In a spacious mixing bowl, thoroughly whisk together the all-purpose flour, baking powder, baking soda, salt, and granulated sugar.
03 - Add the cold, cubed butter to the dry ingredients. Using a pastry cutter or your fingertips, work the butter into the flour until the mixture achieves a texture of coarse crumbs with discernible pea-sized pieces.
04 - Form a well in the center of the flour-butter mixture and pour in the cold buttermilk. Gently stir with a fork just until the dough barely comes together; take care not to overmix.
05 - Transfer the dough onto a lightly floured surface. Gently pat it into a rectangle approximately 1-inch thick. Fold the dough in half, then pat it out again. Repeat this folding and patting process 2 to 3 times to develop layers for flakiness.
06 - Using a 2.5-inch biscuit cutter, firmly press straight down to cut out biscuits; avoid twisting the cutter. Gather any dough scraps, gently re-pat them, and cut additional biscuits until all dough is used.
07 - Arrange the cut biscuits on the prepared baking sheet, ensuring their sides are lightly touching. Lightly brush the tops of the biscuits with a small amount of extra buttermilk.
08 - Bake for 12 to 15 minutes, or until the biscuits are beautifully golden brown on top. Carefully remove from the oven and serve warm.