Tarka dal

INGREDIENTS

• 250g/9oz chana dal (yellow dried split peas), rinsed until the water runs clear
• 1 litre/1¾ pints water
• 3 tbsp vegetable oil
• 1 tbsp cumin
• 1 small onion
• 3-4 whole green chillies, pricked with a knife
• 2cm/¾in piece fresh ginger
• 3 garlic
• 3 tomatoes
• ¾ tsp ground turmeric
• ¾ tsp garam masala
• 1½ tsp ground coriander
• salt and freshly ground black pepper
• handful chopped fresh coriander