Step 1

Heat the oven: Arrange a rack in the middle of the oven and heat to 450°F.

Step 2

Mix the dry ingredients: Whisk the flour, baking powder, baking soda, and salt together in a medium bowl; set aside.

Step 3

Grate the butter: Place a box grater over a small piece of parchment paper. Grate the frozen butter on the large holes of a box grater. When you get down to a small nub of butter, chop that nub into 5 to 6 small pieces.

Step 4

Add the butter to the dry ingredients: Use the piece of parchment paper to transfer the butter to the dry ingredients. Use your fingers to sift the butter into the flour and break up any clumps of grated butter.

Step 5

Mix in the buttermilk: Pour in the buttermilk and beat it in with a wooden spoon until the dough comes together and pulls away from the sides of the bowl.

Step 6

Fold the biscuits: Transfer the dough to a lightly floured cutting board. Pat the dough into a 1-inch-thick rough rectangle. Sprinkle the dough with a little more flour, if needed. Fold the dough in half from top to bottom, then pat it back down into its original shape. Repeat with the folding and patting, alternating folding from each side, the bottom, and the top until you have completed a total of 8 folds. At the end, the dough should be a little springy to the touch.

Step 7

Cut the biscuits: Pat the dough into a 1-inch thickness. Use a 3-inch round cutter to cut the dough into 6 biscuits. If you don't get 6 the first time around, refold and pat down the excess dough and cut more as needed. Discard the scraps of leftover dough.

Step 8

Bake: Arrange the biscuits in a 10-inch cast iron skillet so that the biscuits touch each other, but not the sides of the pan. Put the skillet in the oven and increase the oven temperature to 500°F. Bake until the biscuits are golden-brown, 15 to 18 minutes.

Step 9

Serve: Remove the skillet from the oven and immediately remove the biscuits from the pan to a clean tea towel.