all about...tea eggs

Tea eggs are simply hard-boiled eggs that have been further stewed in a salted tea liquid. Other flavourings such as soy sauce and Chinese five-spice powder are often added as well. The eggs are actually boiled twice. After the first boiling, when the insides are hardened, the shell of each egg is lightly cracked. The eggs are then boiled for much longer duration in the black tea mixture for a second time, which allows the flavour of the tea to penetrate deep into the egg. The dark colour of the tea also stains through the cracks of the eggs creating a pattern on the peeled eggs that resembles the crazing of some ceramic glaze surfaces. (wiki)