In a large heavy pot over medium heat, warm ¼ cup olive oil. Add the sliced onions and cook until translucent and lightly golden, about 6 minutes. Add the chicken drumsticks and sear on all sides until lightly browned, 4 to 6 minutes. Add the potatoes, zucchinis, celery, and carrots and cook, stirring, for 3 to 4 minutes.

In a small bowl, stir the tomato paste with the sweet paprika, hot paprika, turmeric, black pepper, baharat, and a little oil to form a smooth paste. Add the spice paste and salt to the pot and stir to coat the chicken and vegetables. Pour in enough hot water to just cover the ingredients. Cover and simmer for 30 minutes.

Uncover and add the cubed pumpkin, chopped cabbage, and cooked chickpeas (if using soaked, uncooked chickpeas, they should have been added at the start). Simmer uncovered for 20 minutes more, until the vegetables are tender and the broth is richly colored and seasoned. Adjust salt and pepper to taste.

Ladle the soup into a wide serving pot and serve immediately alongside steamed, fluffy couscous.