Heat the olive oil in a large saucepan and fry the garlic, onion and celery for 4-5 minutes. Add the chickpeas to the pan and cook for a further 10 minutes.
Now add the finely chopped mint, stirring well, and then pour over the vegetable broth and tahini. Bring to the boil, reduce heat to low and simmer for at least 30 minutes. Season to taste with salt and freshly ground black pepper.