Preheat oven to 500 degrees. Line a baking sheet with a silicone baking mat. (You can also bake the biscuits on an ungreased baking sheet.)

In a bowl, combine flour, baking powder, and salt. Using a pastry blender or two knives, cut butter into flour mixture until it resembles coarse meal. Pour in buttermilk and mix until just barely combined. It will be a shaggy mass. (Alternatively, you can mix the dough in a food processor: Pulse to combine flour, baking powder, and salt. Add butter and pulse until it resembles coarse meal. Pour in buttermilk through feed tube and pulse until just barely combined.)

Turn shaggy mass out onto a lightly floured surface. Knead lightly, using the heel of your hand to compress and push dough away from you, then fold it back over itself. Give dough a small turn and repeat four or five times. (You want to just barely activate the gluten, not overwork it.)

Using a lightly floured rolling pin, roll out dough 1 inch thick. Using a 3 1/2-inch round cutter dipped in flour, cut out rounds (press cutter straight down without twisting so biscuits will rise evenly when baked).

Place biscuits on prepared sheet. (If biscuits are baked close together, sides will be tender. If biscuits are baked farther apart, sides will be crisp.)

Reroll scraps once. Do not simply roll them into a ball; this will create a knot of gluten strands. Instead, place the pieces one on top of the other in layers, then roll out dough and cut out more rounds.

Bake until golden brown, 10 to 12 minutes. Transfer to a rack to cool just slightly. Serve warm.