Preheat the oven to 200°C, gas mark 6. Place the aubergine and thyme on a baking tray and bake for 25 minutes or until soft and slightly charred.
Meanwhile, heat the olive oil in a large pot placed over a medium heat.
Sauté the leeks, garlic and celery until soft. Stir in the flour and cook for 1 minute. Stir in the stock, tahini and hot sauce.
Simmer gently for 30-40 minutes, covered.
Once ready, add the aubergine and blend until smooth and season well to taste.
Garnish with the thyme and a swirl of cream.