Onion seeds are small irregular shaped black seeds of the plant that grows in India called Kalonji. The spice can be used fresh or dry-roasted in curries and added to vegetables, relishes, pickles and chutneys, yoghurts as well as in the naan bread dough. The seeds have a bitter and peppery flavour and the taste is further enhanced once the seeds are roasted for 2 minutes or so. Onion seeds are said to be good for skin disorders, soothing an earache and calming an upset stomach.