Preheat oven to 425°F (220°C) and line a baking sheet with parchment paper or a silicone baking mat.

Whisk together flour, baking powder, baking soda, and salt in a large bowl. Add the cold butter slices and cut into the flour until the mixture resembles coarse crumbs.

Make a well in the center of the mixture, pour in cold buttermilk, and stir gently until just combined. Turn dough onto a floured work surface and form a rectangle.

Fold the dough into thirds, turn it 90 degrees, and flatten into a rectangle. Repeat the folding and flattening process two more times.

Roll the dough to 1/2 inch thickness and cut out biscuits using a 2 1/2-inch biscuit cutter. Reroll scraps as needed to make 12 biscuits.

Place biscuits on the prepared baking sheet. Press an indent into the top of each biscuit with your thumb and brush with buttermilk.