1 1/2 c  All-purpose flour
1/2 c  Cake flour
1/2 ts Salt
2 ts Baking powder
1/2 c  Cold unsalted butter
34 c  Buttermilk or more

Preheat the oven to 450F; set rack in middle level. Prepare biscuit dough.
COMBINE THE FLOURS, salt and baking powder in a mixing bowl and stir well
to mix. Rub in the butter by hand or with a pastry blender until the
mixture is mealy. Stir in 3/4 cup of the buttermilk with a fork and
continue stirring gently until the dough begins to hold together. (If the
dough is dry, add more buttermilk, 1 tablespoon at a time.) Sprinkle the
work surface generously with flour and scrape the dough onto it. Fold the
dough over on itself two or three times. Use the dough immediately . Pat
dough into a 6-by-12- inch rectangle and cut into eight 3-inch biscuits
with a sharp, floured knife. Transfer to a parchment-lined cookie sheet.
Paint tops with buttermilk. Bake for 10 to 15 minutes, until well risen and
golden.