Chicken and rosewater biryani

For the marinated chicken

250ml/9fl oz natural yogurt
6 garlic cloves, finely crushed
6cm/2½in (30g/1oz) piece ginger, finely grated
3 green chillies, finely chopped, with seeds
1 tsp Kashmiri chilli powder
1 tsp ground coriander
½ tsp ground turmeric
500g/1lb 2oz skinless, boneless chicken thighs, cut in half

For the crisp fried onions

300ml/10fl oz vegetable oil
3 medium onions, thinly sliced

For the gravy

10 whole cloves
6cm/2½in piece cinnamon stick
5 green cardamom pods, bruised with a rolling pin
2 Indian bay leaves
1 tsp cumin seeds
2 medium tomatoes, chopped
1 tsp salt

For the rice

600g/1lb 5oz basmati rice, soaked in cold water for an hour
1 tsp salt per 1 litre/1¾ pint of cooking water