Coriander plants arrived with Arab and Indian traders in the south of Thailand over a thousand years ago. Thai food use all the plant, so when buying make sure that the stems have roots attached!
The picked leaves (Sometimes called cilantro) are used in Thai food-Salads and Thai food-Soups; the stems are added to stocks, while the roots are a common ingredient in sauces, curry pastes and dipping sauce.
* Thai seafood dipping sauce
Red chilli, Garlic, Fish sauce, Lime juice, Coriander roots, Palm Sugar
Gradually pound the ingredients together using a mortar.
*Thai Curry paste
Chopped Galangal, Chopped Lemongrass, Chopped Kaffir lime zest, Chopped Coriander root, Chopped Red Shallot, Coped Garlic
Gradually pound the ingredients together using a pestle and mortar, adding one by one until smooth.
When shopping for coriander in an Asian Supermarket, looking for coriander with the roots still attached, as not only the stem and leaves can be used for cooking. Coriander roots are an integral part of many Thai food dishes, where they are used as flavouring in soups, marinades and curry pastes. Cut the root with about 1/2″ of green and wash well before adding to the dish. To ensure that the flavours are released, bruise the root in a stone mortar & pestle first. The roots can be frozen for long term storage.
Shopping for Coriander with roots at RaanThai Supermarket