Preheat oven to 200°C/400°F.

Toss carrots, onion, and garlic with olive oil, cumin, coriander, chilli flakes (if using), salt, and pepper on a baking tray.

Roast for 20-25 minutes, or until carrots are tender and slightly browned.

Transfer roasted vegetables to a large pot. Add vegetable stock and bring to a boil.

Reduce heat and simmer for 10 minutes.

Using an immersion blender, blend the soup until smooth. Alternatively, carefully transfer the soup to a regular blender and blend until smooth.

Season to taste with salt and pepper.

Serve garnished with fresh coriander.