First, make the chermoula. Using a mortar and pestle, pound the garlic and chile with the salt to form a paste. Add the cilantro leaves and pound to a course paste. Beat in the saffron and cumin and bind well with the olive oil and lemon juice (you can whizz all the ingredients together in a blender if you prefer). Reserve 2 teaspoons of the mixture for cooking. Cut fish into large chunks and toss with the remaining chermoula. Cover and marinate in the refrigerator for 1-2 hours.

Heat the oil in a tagine or heavy-based casserole dish. Stir in the onion, carrots and celery and saute until softened. Add the preserved lemon (reserving a little for sprinkling) with the 2 tsp of chermoula and the tomatoes and stir well. Cook gently for about 10 minutes to reduce the liquid, then add the stock and the wine. Bring the liquid to a boil, cover the tagine, reduce the heat and simmer for 10-15 minutes. This can be prepared ahead.

When ready to serve, gently reheat the sauce. Toss the fish in the tagine, cover and cook gently for 6-8 minutes, until the fish is cooked through. Season to taste with salt and pepper. Place in serving dishes, sprinkle with reserved preserved lemon and the shredded mint leaves.