Heat the oil in a large frying pan or wok, add the chicken, onion, garlic and chilli and fry for 4–5 minutes until the chicken begins to brown and the onion softens. Add the cardamoms, cumin seeds, dried chilli flakes, ginger and turmeric and fry for a further 1 minute.
Add the spinach, cover and cook gently until the spinach wilts, then stir in the tomatoes, re-cover and simmer for 15 minutes or until the chicken is cooked through, removing the lid for the last 5 minutes of cooking.
Stir the yogurt and chopped coriander into the curry, then scatter over coriander sprigs to garnish. Serve with boiled rice, if liked (remembering to count the extra calories).