1. Heat the oil in a large saucepan or wok over a medium heat and add the garlic, onions and chillies. Cook, stirring frequently, for 6-8 minutes until the onions turn golden brown.
2. Stir in the cumin, coriander, turmeric, salt and cardamom pods and fry for 1 minute, then stir in the tomato puree.
3. Add the chicken pieces, reduce the heat to low and fry, stirring, for 7-8 minutes, or until they change colour. Bring 250ml / 9fl oz / 1 cup water to the boil.
4. Add the water and the coconut milk to the chicken, then add the ground nuts. Simmer, uncovered, stirring occasionally, for 7 minutes, or until the chicken is cooked through. Check by cutting a piece of chicken in half - the juices should run clear.
5. Stir in the ginger and sprinkle over the garam masala. Serve hot.