1. Set a heavy frying kettle on a warm part of the range. Fill it half full of fat. Let it slowly heat to 380° F., or hot enough to turn a 1 inch cube of bread golden brown in 40 to 60 seconds.
2. Peel the onions under water, then cut in slices 1/4-inch thick and separate these into rings.
3. Add salt and pepper to the flour.
4. Dip the rings first in the milk, then in the seasoned flour, then into the hot fat. Fry 3 to 5 minutes. Drain on soft brown paper or paper toweling.