To prepare the harissa with mint glaze, add all of the ingredients to a small bowl and stir well. Use more or less harissa depending on the heat you want.
Divide the glaze between four lamb leg steaks, brushing it on both sides. Set the lamb aside to marinade while you prepare the salad.
To prepare the giant toasted couscous salad, heat the olive oil in a saute pan and lightly toast the couscous until golden, stirring constantly. Take care that it does not burn as it will begin to change colour quickly.
Add the water, bring to the boil and allow the couscous to simmer for 6-8 minutes until all of the water has been absorbed.
Transfer the cooked couscous to a plate and leave to cool to room temperature.
Add the cucumber, tomatoes, olives, spring onion, parsley and feta to the cooled couscous and toss gently.
Drizzle over the lemon-infused olive oil and season the salad to taste. Chill in the refrigerator until needed.
BBQ the lamb for 6-8 minutes on both sides. Serve with the toasted couscous salad and a dollop of plain natural yogurt, if desired.
If you don't have lemon-infused olive oil use 4 tbsp extra virgin olive oil and the juice from 1/2 a lemon.