Pick over the beans and discard any stones or debris. Soak the beans in a large bowl with plenty of water overnight. The next day, drain the beans, place in a saucepan and cover with water by 2-inches. Bring to a boil over high heat, reduce the heat to low and simmer until tender, 45 to 60 minutes. Strain the beans and reserve the cooking liquid. Puree about half the beans with the cooking liquid to make a smooth paste. Reserve.
In a large soup pot over medium heat, warm the olive oil. Add the pancetta and cook just until it starts to turn golden. Add the onions, carrots, celery, rosemary and garlic and cook stirring occasionally until the vegetables are soft, 10 to 12 minutes.
Add the farro, the bean puree, kale, 2 cups of water, chicken stock. Bring to a boil and simmer over low heat for 15 minutes. Add the whole beans and continue to cook until the faro and kale are tender and the soup is thick, 45 to 50 minutes. Season to taste with salt and pepper.
Ladle into bowls, drizzle with olive oil and serve immediately.
Note: * Farro is an ancient grain with a delicious and nutty flavor. I use Village Harvest Farro Perlato.