Heat 1 tablespoon of sesame oil. Cook 1 finely chopped red onion over low heat for 10 minutes.
Add 1 clove of crushed garlic, 1 thumb-sized piece of grated ginger, and 1 finely chopped red chili. Cook for 1 minute.
Stir in 1½ teaspoons of turmeric and 1½ teaspoons of ground cumin. Cook for 1 minute.
Cut 400g of sweet potato into ¾in / 2cm cubes. Add it to the pan with 250g of rinsed split red lentils and 600ml of vegetable stock. Bring to a boil.
Cover and simmer for about 20 minutes, stirring occasionally, until the lentils and sweet potato are tender. Add a splash of water if it starts to stick.
Stir in 80g of spinach until wilted. Add salt to taste.
