Heat the oil in a large pan over a medium-high heat. Add the onions, carrots and celery and saute for 5 minutes, before stirring in the garlic and spices and cooking for a further couple of minutes, stirring constantly.
Add in the lentils, harissa paste and vegetable stock and bring to the boil, then reduce and simmer for 15 minutes, before adding the chickpeas. Cook for 5 more minutes.
Stir in the lemon juice and coriander, taste test and add salt if needed. Serve with a little coconut yoghurt, fresh coriander and a hunk of bread and butter. Enjoy! If preparing in advance, this soup will last 5-6 days in the fridge.