Instructions

1. Peal and dice the sweet potatoes and put them in a saucepan.
2. Rinse the lentils well, then add to the sweet potatoes together with the turmeric and tomatoes. Add about a litre of water and bring to the boil. Gently simmer for 15 minutes under cover.
3. Meanwhile, thinly slice the onion, chop the garlic, chilli and ginger.
4. Heat the oil in a frying pan and gently sauté the onion until soft. Add the garlic, chilli and ginger. Stir for a few seconds, then add the seeds and curry leaves. Keep stirring for a minute or so, until the seeds start to pop. Add the ground spices and stir until fragrant.
5. Stir the spice mixture into the stew and cook for another 10 minutes until you get a thick, creamy pottage. Stir in the lemon juice and some chopped coriander leaves.
6. Serve with sliced spring onions or coriander leaves.