Sauté the diced onions and garlic in the pot on low heat just to sweat the onions. While doing so, pan fry the chicken legs in a separate pan just to get a golden brown on both sides.
Add the cumin, ginger and turmeric to the onions and garlic.
Place the chicken legs side by side into the pot with the onions and add a light chicken broth (unsalted) just enough but not covering the chicken. Add the sliced preserved lemon and green olives. The lemon is sour and salty so there is no need to add any salt to this dish.
Let the broth reduce, add the harissa and stir. Turn the chicken over and spoon the sauce over the meat.
When the chicken is cooked, garnish with chopped coriander, dried whole chilis and sliced preserved lemon.