Black onion seed is not to be confused with cumin or caraway. Dark black onion seed has a light marjoram aroma and an earthy nutty flavor similar to sesame seeds. Kalonji is often called onion seed but in fact has nothing to do with onions. TRS Kalonji (Onion Seeds) can be used for various oriental dishes. It is an essential ingredient of chutneys and vegetable dishes. However usually, kalonji is used in Turkish flat bread or Indian naan bread.