Heat olive oil in a large saucepan on high heat.

Brown chicken thighs in batches for 2-3 minutes per side. Set aside.

Add chopped onion, crushed garlic, finely grated ginger, ground cumin, ground coriander, ground sweet paprika, ground cinnamon, and saffron threads to the saucepan.

Sauté the aromatics for 2-3 minutes, until the onion is tender. Add plain flour.

Cook the flour, stirring, for 1 minute.

Gradually blend in chicken stock and bring to a boil.

Return the browned chicken to the pan.

Simmer, covered, for 30 minutes, or until the chicken is tender and cooked through.

Stir in whole green olives, chopped preserved lemons, and 2 tablespoons of chopped cilantro.

Cool the tagine slightly.

Combine couscous in a large bowl with boiling water.

Cover the bowl with plastic wrap and let it stand for 5 minutes.

Fluff the couscous with a fork. Add the remaining chopped cilantro and stir through.

Cool the couscous slightly.

Serve the chicken tagine with the couscous.