Heat the oven to 425°F (218°C) and set aside an oven-safe 10-inch or 12-inch skillet like a cast iron pan or, if you do not have one, set aside a baking sheet instead.

Combine the flour, baking powder, baking soda, sugar, and salt in the bowl of a food processor. Pulse three to four times so that it is mixed.

Cut the cold butter into cubes or thin slices, then scatter it over the flour in the food processor. Pulse 5 to 7 times or until the butter turns into tiny bits.

Empty the butter-flour mixture into a large bowl. Make a well in the middle, and then pour in the milk (or buttermilk). Stir until a shaggy dough forms.

Transfer the dough onto a lightly floured work surface. Sprinkle a little flour on top, and then bring the dough together with your hands. It might be a bit sticky, so add flour as needed.

Without working the dough too much, pat it down into a rectangle about ¾ inch thick. Fold the dough into thirds, like a letter. Rotate the rectangle 90 degrees, and then repeat this process two more times.

Pat the dough into a rectangle between ½ inch and ¾ inch thick. Then use a biscuit cutter to cut out your biscuits — a 3-inch round cutter is recommended.

Place the cut-out biscuits into the skillet (or onto a baking sheet). Place them close to each other.

Gently press together the scraps and use them to make more biscuits, being careful not to overwork the dough.

Bake the biscuits until golden brown and have risen, 10 to 15 minutes. Serve warm.