Nigella seeds are not generally included in cooking except as a topping for Indian naan bread. North African bakers often knead them into white breads. Slight oregano flavor.
Once you are familiar with the taste, the black dots add interest as a finishing touch to plain rice and to vegetables, especially such sweet ones as carrots and parsnips. They can also be used in salad dressings and are especially good on a simple, onion-free tomato salad.