For the carrots, in a large saucepan over a medium heat, bring the carrot juice and 100ml/3½fl oz water to the boil, then add the salt and cumin. Add the carrots and simmer gently for 10 minutes, or until they are cooked through. Remove from the heat, remove the carrots and reserve the cooking liquor.
For the barley, in a medium, lidded saucepan over a medium heat, heat the oil and gently fry the onions and chillies for 5 minutes, covered with a lid, until softened. Stir in the barley and cumin and continue to fry for a minute. Add 500ml/18fl oz of the carrot cooking liquor to the pan. Bring to a gentle simmer, then cover with the lid and cook for 50–55 minutes, stirring from time to time, until the barley swells and is firm with a good bite. Check the texture, taste and season with salt and pepper. Cook for a few minutes more, if necessary. Set aside in the pan.
To finish the barley risotto, using a long knife, carefully cut the kernels off the corn cob by running a knife along the central core. Keep 4 of the biggest lengths intact to use as garnish. Set these aside then release the kernels from the rest. Add the chard stems and leaves, spring onions and loose corn kernels to the barley pan and stir. Place the pan back on a medium heat and cook for 12 minutes. Add the coriander and cook for a further minute until wilted. Finally, taste and adjust the seasoning if required, then add the lemon juice to sharpen the flavour.
To finish, in a frying pan over a medium heat, fry the cooked carrot pieces in the rapeseed oil for 6–7 minutes, until caramelised. Add the reserved pieces of sliced corn to the pan and cook for 3 minutes, or until they begin to brown.
To serve, remove the caramelised carrots, add them to the barley risotto and divide the risotto evenly between four plates. Finish with a length of sliced corn and micro coriander, if using. Serve immediately.