Preheat the oven to 200°C. Line a baking sheet lined withbaking paper.
Place the carrots on the baking sheet and drizzle with 1tablespoon of olive oil and roast in the oven for 20 minutes.
Heat half of the remaining oil in a large pot and fry the shallots for3-4 minutes. Remove half of the shallots from the pan and setaside. Add the garlic, potato, turmeric and roasted carrots to thepot. Pour in the broth and bring to a boil, then reduce the heat tolow and simmer gently for 15 minutes.
Meanwhile, toast the bread and cut into small pieces.
Add 3 tablespoons of tahini, the lemon zest and 2 tablespoons oflemon juice to the soup.
Puree the soup to a smooth consistency with an immersionblender. Taste the soup and season with salt, pepper, or morelemon juice if necessary.
To serve, divide the soup between 4 bowls, top with set asideshallots, croutons and drizzle with the remaining tahini.