- Preheat the oven to 200ºC/Fan 180ºC.
- Warm 2 teaspoons of oil in a roasting tin in the oven. Add the chickpeas and sweet potato to the roasting tin and gently toss to coat with oil. Roast for about 10 minutes.
- Meanwhile, warm the remaining teaspoon of oil in a large non-stick frying pan over a medium heat. Mix together the cumin and cinnamon, and rub over the chicken. Then transfer to the pan and cook for 3–4 minutes until the chicken is browned on all sides.
- Add the browned chicken, lemon zest and juice, and the plum tomatoes (including the juice) to the roasting tin, and gently stir.
- Cover the roasting tin with foil and cook in the oven for 50 minutes.
- Remove the foil and cook for a further 10 minutes, until the chicken is cooked through and the sweet potato is tender.