This is a classic soup from the Garfagnana, a region in the hills above Lucca. Some versions of Farro soup add thinly sliced kale to this basic rich and filling soup. Others cook a piece of prosciutto along with the beans for a meatier flavor and omit the pancetta as part of the soffritto.
Soak the beans in ample cold water to cover overnight. The next morning drain the beans and rinse well. Add fresh cold water to cover the beans by 3 inches. If using ham or prosciutto, add it to the beans. Bring to a boil and reduce heat. Simmer covered until tender but not soft, about 40 minutes. Add 1 teaspoon or more salt during the last 15 minutes of cooking. You should have about 3 cups cooked beans. Save cooked beans with their liquids. Set aside about 3/4 cup of beans and puree the rest with their cooking liquids in a food processor or blender until a coarse puree is formed. The meat can be chopped and added back to the soup or pureed with the beans.
Warm the olive oil in a soup pot and sauté the diced pancetta over medium heat. When the pancetta starts to give off some fat, add the chopped vegetables and stir well. Sauté for about 8-10 minutes then add garlic, tomatoes, and sage and about 3 cups of water. Bring to a boil and reduce heat. Simmer for about 20 minutes. Add the farro and stir well.
Cover the pan and simmer covered until the farro is cooked, about 40 minutes. Check from time to time and if the mixture seems dry, add boiling water as needed. Add the bean puree and the beans. Stir well and simmer 20 minutes longer. If you like, add the thinly sliced kale when you return the beans to the pot. Stir from time to time to prevent scorching, adding water as needed. Adjust seasoning and serve soup drizzled with additional extra virgin olive oil, grated cheese and if you like, some parsley.
