Heat a soup pot on medium heat. Add olive oil to the pot and then add chopped onions, celery, carrots, and garlic. Sweat (gently cook, no browning) the vegetables until the onions become translucent.
Next, add salt, pepper, red chili flakes, and tomato paste. Stir in and let warm until the tomato paste is starting to caramelize.
Then, add soaked borlotti beans and stir to coat in fat and flavor.
Add chicken broth, and simmer on low heat with the lid on for 35-40 minutes, or until the beans are very soft.
Once the beans have fully softened, use an immersion blender and puree until the soup is very smooth. (A countertop blender can be used. Let soup cool a bit before blending.)
Add farro to the blended soup. Cover and simmer on low for an additional 35-40 minutes, until the farro is plump and tender.
Taste and adjust seasoning to taste.
Serve with a drizzle of extra virgin olive oil and a pinch of flaky sea salt.