Preheat your Oven to 450°F. Line a Baking Sheet with Parchment Paper (or leave it unlined — a bare sheet gives a slightly crispier bottom).

In a large Mixing Bowl, whisk together the 2 cups all-purpose flour plus more for dusting, 1 tbsp baking powder, ¼ tsp baking soda, 1 tsp kosher salt, and 1 tsp granulated sugar until evenly combined.

Add the cold 6 tbsp unsalted butter very cold, cut into 1/4-inch cubes cubes to the 2 cups all-purpose flour plus more for dusting mixture. Using your fingertips, quickly press and smear the 6 tbsp unsalted butter very cold, cut into 1/4-inch cubes into the 2 cups all-purpose flour plus more for dusting until the mixture resembles coarse, shaggy crumbs with some pea-sized pieces of 6 tbsp unsalted butter very cold, cut into 1/4-inch cubes remaining. Work fast — the 6 tbsp unsalted butter very cold, cut into 1/4-inch cubes must stay cold. You can also use a Grater to grate frozen 6 tbsp unsalted butter very cold, cut into 1/4-inch cubes directly into the 2 cups all-purpose flour plus more for dusting.

Make a well in the center of the 2 cups all-purpose flour plus more for dusting-6 tbsp unsalted butter very cold, cut into 1/4-inch cubes mixture and pour in the cold ¾ cup buttermilk very cold, plus more for brushing. Using a fork or Spatula, stir and fold gently until the dough just comes together into a shaggy mass. Do not overmix — a few dry streaks are okay at this stage.

Turn the dough out onto a lightly floured surface. Gently pat it into a rough rectangle about 3/4-inch thick. Fold it in thirds like a letter (fold one side to the center, then the other side over the top). Rotate 90°, pat out again to 3/4-inch thick, and repeat the fold one more time. This lamination creates the flaky layers.

After the final fold, pat the dough to 1-inch thickness. Using a sharp 2.5-inch Biscuit Cutter, press straight down — do not twist — and cut out biscuits as close together as possible. Press the scraps together gently and cut out remaining biscuits (these may be slightly less layered, but still delicious).

Place the biscuits on the prepared Baking Sheet so they are just barely touching each other (about 1/4-inch apart). This helps them rise tall and straight. Brush the tops lightly with ¾ cup buttermilk very cold, plus more for brushing.

Bake at 450°F for 12–14 minutes, until the tops are deep golden brown and the biscuits have risen tall. Rotate the pan halfway through for even browning.

Remove from the Oven and brush immediately with melted 6 tbsp unsalted butter very cold, cut into 1/4-inch cubes if desired. Let cool for 2–3 minutes, then serve warm.