Chop all the vegetables into small cubes: pumpkin, onion, carrot and celery. Put in a saucepan,and add 1 liter of water, salt and cover and bring to the boil. Add the washed farro, the roasted chestnuts and beans, sage leaves; cover with a lid and cook for 40 minutes.
In a small pan, fry two tablespoons of oil with a clove of crushed garlic; then add the mushrooms and leave them to cook for a couple of minutes
After 40 minutes add the garlic and mushrooms to the soup with the cooking oil to the soup. Mix well and continue cooking for another 5 minutes or until the soup has reached the desired consistency and creaminess.
Season with salt and pepper and let it rest for 5 minutes and serve.