Cauliflower with lentil curry

3 tbsp vegetable oil

1 onion, finely chopped

1 large garlic clove, finely chopped

25g fresh root ginger, grated

2 tsp ground coriander

2 tsp ground cumin

½ tsp ground turmeric

75g red split lentils

150ml vegetable stock, hot

1 cauliflower, cut into small florets

1 large carrot, peeled and diced

400ml tin light coconut milk

75g frozen green beans, thawed

3 tbsp chopped fresh coriander

1 tbsp lemon juice

Salt and freshly ground black pepper

Fresh coriander to garnish