Heat the sunflower oil in a large soup pan over a medium heat. Add the onion, carrots and celery and saute gently for 5 minutes taking care to soften but not brown the vegetables.
Add the garlic, ginger and chilli to the pan and continue to saute gently for a further 2-3 minutes.
Add the dry spices to the pan and stir well to combine. Cook for 1 minute until the spices start to release their aroma.
After a good rinse under cold water, add the lentils and the tinned tomatoes to the pan along with the vegetable stock. Bring the soup to the boil before turning down to a simmer and covering with a lid. Stir the soup from time to time to avoid it sticking. The soup should cook for 40 minutes or until the lentils have softened.
Once cooked, blitz the soup with a stick blender. Season to taste and serve when ready.
If you wish to add a creamy element to this soup, you can stir through either a spoon of natural yogurt or if following a vegan or dairy-free diet, a spoon of coconut milk, just before serving.