Combine the spices in a dry sauté pan set over low heat. Toast until fragrant, about 2 minutes. Transfer to a bowl to cool.

Preheat oven to 350. Season chicken thighs with salt, pepper, and 2 tablespoons of spice mix with 2 tablespoons of olive oil.

Bring salted water to a boil in a large pot. Prepare a bowl of ice water. Core tomatoes and score an X on their bottoms. Boil cauliflower florets for 3 minutes, then submerge in ice water. Boil tomatoes for 20 seconds, then chill in ice water. Remove and dry cauliflower, peel skin from tomatoes, and cut into quarters.

In a large sauté pan, heat remaining olive oil over medium heat. Sear chicken in batches until browned and transfer to a Dutch oven. Remove excess fat and brown cauliflower, then add to chicken.

Reduce heat and add onion, garlic, ginger, and saffron. Cook until onions are translucent, about 5 minutes. Add tomato paste and chicken stock; simmer until reduced by 1/3.

Pour sauce over chicken and cauliflower, cover, and transfer to the oven for 20 minutes. Stir in tomatoes, preserved lemon, and olives, cover, and cook for an additional 20 minutes until chicken is cooked through. Serve with cilantro leaves and couscous.