Prepare a chicken stock with the chicken, onion, celery, carrot, bay leaf, thyme, pepper corns and salt, cover up in cold water, bring to the boil and set to simmer for 1 hour. To prepare the soup, Cook the chopped vegetables together with the pancetta in melted butter until soft but not browned. Cut the mushrooms in quarter and add to the vegetables. Strain the chicken stock and pour over. Shred the chicken meat coarsely and add to the soup, simmer gently for 10 minutes. Stir in the gnocchi and cook for further 5 minutes, Thicken the soup to the desired consistency with diluted corn flour, stir in the spinach leaves and serve piping hot with a pinch of lemon zest and grated nutmeg.