Combine the spice, olive oil, lemon juice and red wine vinegar in a small bowl and leave for at least 10 minutes for the flavours to develop.
Preheat the BBQ or a grill pan on your stove, then toast the cashews.
Coat the chicken thighs in Chimichurri sauce, (keeping a few teaspoons for serving) and set aside for a further 10 minutes (or longer if possible) to marinate, in the meantime, roughly chop the barberries and the cashews.
Place the chicken, skin side down, on the BBQ or in the pan and cook for about 5 minutes or until the skin is golden and crisp, then cook for a further 5 minutes on the other side.
Turn the heat to low and continue to cook for another 20 minutes with the hood down or the pan covered loosely in foil, until the chicken is cooked through.
While the chicken is cooking, break the cauliflower into florets and cut away as much of the stalk as you can.
Place half the florets in a food processor and blitz until the cauliflower resembles couscous, be careful not to be left with a puree consistency; then repeat with the other half.
Heat a large pan on the stove and add 2 tablespoons of olive oil.
Add the blitzed cauliflower and garlic and cook over a medium heat for about 6 minutes, then combine cauliflower, remaining 2 tablespoons olive oil, lemon juice, cashews, barberries, Chimichurri, parsley and salt in a large bowl.
Transfer the chicken and the cauliflower couscous to a serving plate and drizzle with the remaining Chimichurri sauce.
Serve with Greek yoghurt and extra parsley for garnish.
Serve without the yoghurt for a dairy-free and paleo option.