Cut butter with a sharp knife or pastry blender into 1/4-inch-thick slices. Sprinkle butter slices over flour in a large bowl. Toss butter with flour. Cut butter into flour with a pastry blender until crumbly and mixture resembles small peas. Cover and chill 10 minutes.

Add buttermilk, stirring just until dry ingredients are moistened. Turn dough out onto a lightly floured surface; knead 3 or 4 times, gradually adding additional flour as needed.

With floured hands, press or pat dough into a 3/4-inch-thick rectangle (about 9 x 5 inches). Sprinkle top of dough with additional flour. Fold dough over onto itself in 3 sections, starting with 1 short end. (Fold dough rectangle as if folding a letter-size piece of paper)