- Peel and segment the oranges. Whisk together the orange juice, wine (if using) and cornflour in a small saucepan until smooth. Bring to the boil over medium-high heat and cook, stirring, for about 2 minutes or until the sauce thickens. Remove from the heat and stir in the orange segments. Keep warm.
- Mix the coriander, cornmeal and pepper in a shallow dish. Coat both sides of the tuna steaks with the cornmeal mixture, pressing firmly so it adheres.
- Heat 2 teaspoons of the oil in a large, heavy frying pan over medium-high heat until hot but not smoking. Sear the tuna for about 2–3 minutes on each side for medium-rare, or longer according to your taste. Add the remaining oil just before turning the fish. Serve with the sauce.
Some more ideas
Meaty fish such as tuna hold their shape well when cooked like this. You can prepare salmon, swordfish and shark steaks in the same way.
Tuna is a member of the mackerel family, all of which are high in omega-3 fatty acids. Like most fish, tuna is also rich in B vitamins, including niacin and vitamins B1 and B6.