Buttermilk Biscuits

2 cups all-purpose flour
1 tablespoon baking powder
3/4 teaspoon salt
1/2 teaspoons baking soda
5 tablespoons chilled solid vegetable shortening
1 cup buttermilk

1. Preheat oven to 425ºF. In a large bowl, sift together flour, baking powder, salt, and baking soda. Using a pastry blender or two knives, cut shortening into the flour mixture until coarse crumbs form.
2. Add the buttermilk, tossing with a fork until a dough forms.
3. Turn dough out onto a lightly floured surface. Gather into a disk. Knead lightly a few times just until smooth. (The dough can be made up to 2 hours ahead, wrapped in plastic wrap, and refrigerated until ready to use.)
4. Pat the dough to 3/4-inch thick. Using a biscuit cutter or a glass dipped in flour, cut out biscuits. Place the biscuits, 2 inches apart, on an un-greased baking sheet. Gather dough trimmings, pat to 3/4 inch-thick, and cut out more biscuits.
5. Bake the biscuits until golden, 12 to 15 minutes. Serve hot.