Cut butter in small pieces and place in freezer for at least 15 minutes. (Longer is fine.)
Weigh the dry ingredients into the work bowl of a food processor. Blend.
Add the butter from the freezer, blend very briefly, until butter is just barely cut in but still in pieces.
Add buttermilk, and blend very briefly.
Turn out onto a piece of waxed paper, and just work the dough enough to pull it together. Cover with more waxed paper, and roll out.
Use a biscuit cutter or other round cutter to cut biscuits. Roll scraps together for the last - work the dough as little as possible.
Bask at 425 for 15 minutes or until done.