A salted duck egg is the cured egg of a duck. This type of egg is usually packed in brine or charcoal for curing. This food is a common ingredient used in many Chinese foods, including stir-fry, soups, salads, and meat dishes. Generally, they are served steamed or hard boiled, either on their own or as part of another dish. The process of salting the egg raw before hard boiling makes the egg white markedly salty with a creamy, rich, and slightly salty yolk center. These eggs are an important part of Chinese moon cakes.
Chinese salted duck eggs are made either by soaking eggs in a bath of mildly warm, extremely salty water or by packing individual eggs in a paste made from charcoal and salt. The charcoal-packed form of the salted duck egg is becoming less common over time, but brined duck eggs are still a nearly ubiquitous food in China. Though the food commonly known as a salted duck egg is Chinese, a similar Filipino dish called pateros cures the eggs using a paste of clay, water and salt. The clay on the egg turns it a bright red color.
This food is cured raw, but the cured eggs are cooked before they are eaten, usually by hard boiling them. Before the salted duck eggs are packed for curing, they are thoroughly washed to remove dirt or contaminants. Once they are clean, they are placed in a slightly warm, highly salted brine or packed in salted charcoal. While many eggs can be liquid brined in the same container, the salty charcoal paste is used to pack each individual egg. The layer of salty charcoal on the egg is generally slightly thicker than the width of a standard pencil.
A common accompaniment for the salted duck egg is fresh tomato. One popular way of serving salted duck egg is in a salad of sliced fresh tomato and salted duck egg. It is also frequently prepared in soups flavored by peppers, gourds, or berries.
The methods of preparation used to make a charcoal-packed Chinese salted duck egg is somewhat similar to another famous cured Chinese duck egg called the century egg, except the century egg is packed in ashes and lime in addition to salt and clay. Though they are often erroneously thought to be duck eggs soaked in horse urine, they are actually many varieties of eggs. They are not packed in horse urine, though they may smell like it, as the curing egg turns black over time and takes on the scent of ammonia and sulfur. Affinity for the century egg is fairly uncommon in China, while the salted duck egg is a common and popular ingredient.