Despite their name, the “thousand-year-old eggs” are not that old!
Thousand-year-old eggs (also called century eggs) are preserved duck eggs (皮蛋 - pe`ih-daahn in Cantonese). You can easily find them at wet markets. The century eggs are covered with mud and chips and left to ferment – not for a century – but up to 100 days. After that period the white has turned to opaque black and its texture is gelatin-like. The yolk has become black-greenish, is creamy and has a pungent alkaline taste.
The outside is gelatin-like / inside is creamy and has a strong alkaline taste