Flaky and buttery.
2 c flour
2 t baking powder
1/4 t baking soda
1 t salt
7 T unsalted butter, cut into thin slices, chilled in freezer
1 c cold buttermilk, divided
In large bowl, combine flour, baking powder, baking soda and salt. Using a pastry blender, fork, or two knives, cut in butter until fine and crumbly. Add 3/4 cup buttermilk. Mix only until dough forms. Handling as little as possible, dump dough onto floured surface and roll/pat into rectangle shape. Fold into thirds, like a business letter. Turn the dough a quarter turn and fold into thirds again. Turn a quarter turn again and fold in thirds again. Roll dough out to 3/4-inch thickness. Using a 2½-inch circle cutter, cut out biscuits by pushing straight down, not twisting.
Place biscuits on ungreased baking sheet. Press the middle of each biscuit with your thumb (helps them raise straight). Brush top of each biscuit with remaining buttermilk. Bake at 425 for 13 minutes.
FYI:
grate frozen butter using coarse grater instead of using pastry blender
if the buttermilk is cold, it tenderizes the dough
if using salted butter, omit salt in recipe
handling dough too much makes for tough biscuits
folding the dough in thirds three times gives you flaky layers
pushing straight down with the cutter gives you straight biscuit sides
