German Fried Potatoes

Slice cold boiled potatoes one-eighth an inch thick (there should be two and one-half cups). Put four tablespoons “fried out” salt pork fat in an iron spider; when hot, add one sliced onion, cook until onion is delicately browned; remove onion and keep warm, add potatoes, season with salt and pepper, mix thoroughly with fat, shaking the spider occasionally when potatoes are browned, add onion; when thoroughly mixed and heated, turn into hot dish and serve at once.