Barbarella, the coriander roots are used in Thai cooking. You only need a little bit, but apparently it's an important ingredient to give the right flavour to some Thai dishes. I'm lucky to have a great Thai food store where I live, and if you can find the ingredients here are two fabulous recipes I often use and that include coriander root; they are from a blog from a Thai friend who's now a professional food blogger (she uses the American name for coriander, cilantro):
- Proper Thai green curry (I make it with chicken and small green Thai aubergines):
http://chezpim.typepad.com/blogs/2003/07/green_curry_gan.html. By the way, the picture on that page is wrong, that's not the green curry.
- Thai marinated fried chicken:
http://www.chezpim.com/blogs/2008/11/thai-marinated.html. This doesn't have a strong "ethnic" taste; it tastes like a lovely garlicky, crisp tasty fried chicken, and you wouldn't guess that "that extra something" comes from Thai ingredients. Using rice flour instead of normal flour was a revelation, the chicken is crispier and less greasy this way.
I'm going to grow coriander too this year because of these recipes, since I can get the coriander with the roots at the Thai shop, but they only sell big bunches and I only need a bit, and coriander really doesn't keep so I always end up throwing away most of it.