Chop 5 of the carrots into 1-inch pieces and add to a saucepan with the onion and potato. Cover with the boiling water, add in the stock pot and simmer for 10 minutes.
Crush the coriander seeds in a heavy pestle and mortar - you can use ground coriander but there tends to be more flavour in the whole seeds. Add to the saucepan.
Meanwhile, julienne the remaining carrot into thin matchsticks. Add to the air fryer and spray with low-calorie cooking spray and a pinch of salt. Air-fry at 180°C for 8-10 minutes until crispy.
Add half of the chopped coriander into the saucepan and simmer for a further 10 minutes until the carrots and potato are tender.
Blitz the soup with the stick blender until smooth. If it is too thick, add a little extra boiling water. Add the remaining fresh coriander blitz again.
Serve while hot, topped with the carrot matchsticks and a sprinkle of extra fresh coriander – if you like!