Heat 1 tbsp sesame oil in a wide-based pan with a tight-fitting lid.
Add 1 finely chopped red onion and cook over a low heat for 10 mins, stirring occasionally, until softened.
Add 1 crushed garlic clove, a finely chopped thumb-sized piece of ginger and 1 finely chopped red chilli, cook for 1 min, then add 1½ tsp ground turmeric and 1½ tsp ground cumin and cook for 1 min more.
Turn up the heat to medium, add 2 sweet potatoes, cut into even chunks, and stir everything together so the potato is coated in the spice mixture.
Tip in 250g red split lentils, 600ml vegetable stock and some seasoning.
Bring the liquid to the boil, then reduce the heat, cover and cook for 20 mins until the lentils are tender and the potato is just holding its shape.
Taste and adjust the seasoning, then gently stir in the 80g spinach. Once wilted, top with the 4 diagonally sliced spring onions and ½ small pack torn basil leaves to serve.
Alternatively, allow to cool completely, then divide between airtight containers and store in the fridge for a healthy lunchbox.