Heat the olive oil in a cooking pot. Add the onion and garlic, fry till translucent, then add the carrots, celery, paprika, turmeric, cumin, cinnamon, salt and pepper. Mix well and cover with water. Allow to simmer, lid on, for about 15 minutes over medium heat.
To the pot, add the lentils, potato and courgettes. Add the passata and just enough water to cover the vegetables. Allow to cook with the lid on for 20 to 25 minutes. At the end of the cooking time, season to taste and add the coriander.
While the vegetables are cooking, melt the butter in a large frying pan over high heat and brown the chicken thighs on one side until well cooked. Turn the thighs over and sprinkle the golden brown side with turmeric, cumin and paprika. Allow the chicken to cook thoroughly. When the chicken is cooked, add salt and pepper. Remove the chicken from the pan and keep warm.
For the couscous:
Scrape the bottom of the pan with a wooden spoon to loosen the cooking juices. Add water and bring to the boil. Next, add the couscous and remove from the heat. Set to one side till the couscous has absorbed the water. Fluff with a fork and taste for salt.
To serve, add couscous on plates and put the vegetables on top. Add the chicken on the side and garnish with coriander. Drain the raisins and serve them on the side.