- Adjust an oven rack to the middle position and heat the oven to 450 degrees F.
- Place the flours, baking powder, baking soda, sugar, and salt in a large bowl or the work bowl of a food processor fitted with the metal blade. Whisk together or process with six 1-second pulses.
- If making by hand, use two knives, a pastry blender, or your fingertips to quickly cut in the butter until the mixture resembles coarse meal with a few slightly larger butter lumps. If using a food processor, remove the cover and distribute the butter evenly over the dry ingredients. Cover and process with twelve 1-second pulses.
- If making by hand, stir in the buttermilk with a rubber spatula or fork until the mixture forms a soft, slightly sticky ball. If using a food processor, remove the cover and pour the buttermilk evenly over the dough. Process until the dough gathers into moist clumps, about eight 1-second pulses.
- Transfer the dough to a lightly floured surface and quickly form into a rough ball. Be careful not to overmix. Pat the dough into a ¾-inch-thick circle. Cut out the dough rounds with a biscuit cutter. Push together the remaining pieces of dough, pat into a ¾-inch-thick, and cut out several more dough rounds. Discard the remaining scraps.
- Place the biscuits on an ungreased cookie sheet. Bake until the biscuit tops are light brown, 10 to 12 minutes. Serve immediately.
* Note 1: If you don’t have cake flour on hand, substitute an extra cup of all-purpose flour and increase the buttermilk by 2 tablespoons.
* Note 2: Once the unbaked biscuits are placed on the cookie sheet, the sheet can be wrapped in plastic and refrigerated for up to 2 hours.