Fermented egg, often referred to as Century Egg or Preserved Egg, is a traditional delicacy in several Asian cuisines, particularly in China. The process involves preserving eggs, typically duck eggs, in a mixture of clay, ash, and salt for several weeks to months. This fermentation alters the egg's flavor, texture, and color, resulting in a dark green or black yolk and a translucent, jelly-like white. The unique taste of fermented eggs is often described as rich and savory, with a slightly pungent aroma. They are commonly served sliced, as a side dish, or incorporated into various dishes, such as congee or salads, adding depth and complexity to the meal.