1.Finely chop the onion. Finely slice the celery then peel the carrot and turnip or swede and cut into similar-sized pieces. Scrape all the veg into your largest saucepan.
2.Add the oil and a good pinch of salt. Cook over a medium heat, stirring occasionally for 15 mins until the veg has collapsed and softened.
3.Meanwhile, peel the ginger then finely grate the ginger and garlic. Add to the saucepan and cook, stirring for 1 min, then stir in the cumin, mustard seeds, turmeric and cinnamon, if using. Cook for 1 min more then pour in the stock.
4.Bring the soup base to a boil, drop in the pearl barley and simmer, stirring occasionally, for 30 mins.
5.After 30 mins, use your hands to shred the turkey meat into small chunks and add to the pan. Cook for a further 5 mins until the meat is heated through, the pearl barley has a pleasing bite and the vegetables are soft.
6.Roughly chop the coriander (stalks and all), then stir most of it through the soup. Finely slice the chilli. Season the soup with salt, pepper and lemon juice to taste, then ladle into bowls and top with the remaining coriander and chilli to serve.