Remove the head and fins from the mackerel, then fillet them making sure no stray bones are left. Score the skin of each fillet twice. Steam the fillets until just cooked through, about 5 minutes. Put the fillets in a shallow dish close together. Cover with the vinegar and leave to marinate for 1 hour.

Drain the vinegar away. Season the mackerel fillets with salt and pepper and the chilli flakes. Scatter the garlic and mint over the fillets. Drizzle with the extra virgin olive oil. Serve with wedges of lemon.

Per serving: 162 Calories (kcal); 8g Total Fat; (46% calories from fat); 18g Protein; 5g Carbohydrate; 45mg Cholesterol; 137mg Sodium Food Exchanges: 0 Grain(Starch); 2 1/2 Lean Meat; 0 Vegetable; 0 Fruit; 1 1/2 Fat; 0 Other Carbohydrates