Preheat the oven to 375 degrees F. In a mixing bowl, combine the dry ingredients and blend thoroughly. Cream in the shortening with your fingers or a fork, until the mixture resembles coarse crumbs. Add the buttermilk a little at a time and, using your hands or a fork, work it in just until its thoroughly incorporated and you have a smooth ball of dough. Do not overwork or overhandle the dough. Lightly floured surface, roll out the dough with a rolling pin to a circle about inches in diameter, 1/2-inch thick. Using a small round cookie cutter or the rim of a shot glass, press out twelve 1-inch rounds. Place the biscuits on a baking sheet and bake until golden brown, about 15 minutes.