Cook the carrots and cauliflower in a large pan of boiling water for 5 minutes, then drain and set aside.
Meanwhile, heat the oil in a large frying pan and cook the onion for 10 minutes until soft, adding the garlic for the last minute. Stir through the harissa paste and chilli powder and cook for a further minute.
Pour in the tomatoes, tomato purée, kidney beans, carrots and cauliflower, stirring to combine. Add 100ml water and the spinach and leave to cook for 10 minutes over a medium heat. Meanwhile, cook the rice and naan following pack instructions.
Stir the spiced veg once or twice, then serve with the rice and naan.