Black bean curry

Name: Black bean curry
Prep time: 30 min
Cook time: 30 min
Total time: 1 h
Cuisine: Asian, Indian
Ingredients: 2 tbsp rapeseed or sunflower oil; 1 medium onion, roughly chopped; 1 tbsp finely grated fresh root ginger; ½ tsp dried chilli flakes; 1 tsp ground coriander; 1 tsp cumin seeds; 1 tsp ground turmeric; 200g/7oz chopped tomatoes, from a tin; ½ tsp fine sea salt, plus extra to season; 400g tin black beans, not drained; squeeze lemon or lime juice; freshly cooked basmati rice; plain yoghurt; fresh coriander; lemon or lime wedges