Preheat oven to 425 F. Sift / stir dry ingredients together. Cut in the butter pieces until texture of corn meal. Stir in Buttermilk, reserving last half cup. Continue adding buttermilk until all ingredients are just lightly moist, and dough begins to stick together. Fold out onto floured surfaced. Knead gently five times. Pat gently into 1/2 " thickness. Cut rounds with biscuit cutter, or squares with knife. Place on lightly greased baking sheet in center of oven. Bake for 13 - 15 min, till lightly brown.