In a large, deep pan, use spray oil or low calorie cooking spray to fry the onion until softened (about 4 minutes)
Add the ginger and garlic, and stir fry for a minute
Stir through the turmeric and smoked paprika
Pour in the vegetable stock
Pour in the drained chickpeas
Add in the sweet potatoes, the white potatoes and the salt
Pour the coconut milk in and stir everything together
Add in the red lentils, and simmer gently for 1 hour. You can cook for longer if you'd like to break down the potato even more for a thicker sauce.
If you'd like some spice, you can add in some chopped fresh red chilli when you add the garlic and ginger, or just sprinkle some dried red chilli flakes on when you serve it. You could replace the potato with butternut squash if you prefer, and some fresh, washed spinach stirred in just before serving is also delicious!