1. Combine the flour, baking soda and salt in a deep bowl. Add the 3 tablespoons of lard bits and, with your fingertips, rub the flour and fat together until they resemble flakes of coarse meal. Pour in the buttermilk or sour milk and beat vigorously with a spoon to make a smooth dough.
2. Over moderate heat, melt the remaining ½ pound of lard in a Dutch oven or heavy casserole about 8 inches in diameter and 4 or 5 inches deep. Heat the fat until it is very hot but not smoking.
3. To shape each biscuit, cut off about 2 tablespoons of the dough and, flouring your hands lightly as you proceed, pat the dough into a ball about 1½ inches in diameter. Drop two or three biscuits at a time into the hot fat, turning them about with a slotted spoon to coat them on all sides with the fat.
4. When all the biscuits have been added to the pot, cover it tightly and fry the biscuits over moderate heat for 4 minutes. Turn the biscuits over with a slotted spoon, cover again and fry for 4 minutes longer, or until they are evenly browned and puffed. Transfer the biscuits to paper towels to drain briefly, and serve them hot.
