Juice half of the lemons, and cut the remainder into wedges. Chop the fresh coriander. Chop the fresh mint.
- 1 Put the sardines in a shallow dish and rub all over with the harissa paste. Pour over the lemon juice, cover and chill for at least 1 hour.
- 2 Prepare the couscous according to the packet instructions. Stir in the butter and fold through the rocket, and half the coriander and mint. Divide between serving plates.
- 3 Mix the yogurt with the remaining herbs and set aside.
- 4 Heat a griddle pan until hot and add the sardines. Cook for 3 minutes each side, until cooked through. Place the sardines on top of the couscous.
- 5 Griddle the lemon wedges for 2-3 minutes until charred, then divide between the plates and serve with the herby yogurt.