In a large pan add the olive oil and onions and cook on a medium heat for 7-8 minutes until soft and browning.
Add in the garlic, celery and carrot. salt, Stir to combine and cook for a 2-3 minutes or so. Add the spices and stir until the veg is coated.
Now add the chopped tomatoes, allow them to soften a little. Next add the stock, lentils and harisa. Simmer for 10 minutes covered then remove the lid and simmer for a further 10 minutes. Add the chickpeas and coriander, stir to combine. Season well.
To make the tahini dressing;
Add all the ingredients to a mini chopper and blitz until creamy.
To serve, Drizzle with tahini dressing, coriander and chilli flakes.