2 chillies, finely chopped, plus extra to taste
4 tsp ground coriander
small handful fresh chopped coriander (optional)
4 garlic cloves, finely chopped
2.5cm/1in piece fresh root ginger, peeled and finely grated
2 onions, finely chopped
2 x 400g cans chopped tomatoes
4 tsp ground cumin
2 tsp garam masala
4 tbsp sunflower oil
2 tsp ground turmeric
200g/7oz natural yoghurt
800g/1lb 12oz beef braising steak, cut into 2.5cm/1in pieces