Duru Karabuğday, known in many kitchens as greçka, is whole buckwheat sold in a practical 1 kg bag, and the label lists a single ingredient: buckwheat. Despite the name it is not a form of wheat. It is the seed of a plant related to sorrel and rhubarb, which is why it is cooked like a grain and has a distinct, toasty, slightly earthy taste.
In the kitchen it behaves much like rice or bulgur. Rinse the groats, toast them for a minute in a dry pan to deepen the aroma, then simmer in roughly twice their volume of water or stock until tender; follow the cooking time printed on the pack. In Turkish homes karabuğday is served as a pilav with sautéed onion and mushrooms, stirred into soups, or cooked into a soft porridge and eaten with yogurt, butter or a little cheese. It also works cold in salads once cooled.
Keep the bag in a cool, dry place and, once opened, move the groats to an airtight jar. Some packs carry a notice about possible traces of gluten from handling, so anyone who must avoid gluten should read the pack carefully before buying.