Brown the lamb: In a heavy pot, heat olive oil and sear lamb chunks on all sides until browned. Remove and set aside.
Make the base: In the same pot, sauté onion until golden. Add garlic, tomato paste, and harissa, cooking until fragrant.
Add tomatoes and spices: Stir in grated tomatoes, cumin, coriander, paprika, turmeric, and cinnamon. Cook for 2–3 minutes until the sauce thickens.
Simmer: Return lamb to the pot, add stock, and bring to a boil. Reduce to a simmer and cook covered for 45 minutes.
Add vegetables & chickpeas: Stir in carrots, potatoes, and chickpeas. Simmer another 30–40 minutes until lamb and vegetables are tender.
Season & serve: Adjust seasoning with salt and pepper. Garnish with parsley and serve hot with couscous or bread, plus lemon wedges on the side.