1. Chop and de-seed the chilli. Drain and rinse the lentils and place in a large saucepan with the onion, potato, chilli, turmeric and water. Bring to the boil, then cover and simmer for 20-25 minutes until the potato is cooked.
2. Chop the spinach and add to the pan with the tomato and cook for a further 8-10 minutes.