Preheat oven to 450°. Place 11/2 cups flour in a large bowl. Add shortening, and use a pinching motion with your fingers to break it up and work it into the flour. (Mixture will be crumbly and resemble small peas.) Add buttermilk and next 2 ingredients, stirring just until flour is moistened.
Turn dough out onto a well-floured surface. Using floured hands, knead dough 4 to 5 times by folding dough over and pressing down with the heels of your hands; gradually add as much of remaining flour as needed to make a smooth dough. (The dough should not be sticky.)
Pat dough to 3/4-inch thickness. Cut with a 2-inch round cutter. (Be very careful not to twist the cutter.) Combine any dough scraps, pat to 3/4-inch thickness, and cut into rounds (discard any remaining scraps). Place biscuits, with sides touching, in an ungreased, light-colored jelly-roll pan.
Bake at 450° for 16 to 18 minutes or until lightly browned.