In reply to Fruitbat:
Buckwheat (not flour) makes the best possible tabbouleh. You can also find it as a filler in some Polish black pudding type sausages.
As for the flour, it can be used anywhere provided you accept that it's not brilliant on its own except in galettes. A lady who ran a boulangerie in France told me I wouldn't be able to make bread out of the "sarrasin" she sold me but she was only half right: mixed 50/50 it makes perfectly good, heavy rolls.
Used in small ratios it can enhance scones , dumplings and even Yorkshire puddings.
But the absolute best incarnation of the plant for me is in the puffed buckwheat you can buy in health food shops : looks just like puffed wheat or rice but has that essential earthy scent and taste of the original plant.