In a large pot, heat the olive oil over medium heat until glistening. Add the chopped onion, celery, carrot and a large pinch each of salt and pepper. Cook, stirring occasionally, until onions are translucent and vegetables have softened, about 5 to 7 minutes.
Add minced garlic and a pinch of red pepper flakes and cook for one more minute. Add the broth, tomatoes, beans and parmesan rind and bring to a boil. Lower heat to a simmer and continue cooking for 10 minutes.
Add cooked farro, spinach and basil and simmer for two more minutes, until spinach is wilted. Taste for salt and pepper and serve warm with lots of grated parmigiano reggiano on top
Notes
*If you buy the bags of 10 Minute Farro from Trader Joe's, you can add the uncooked farro to the soup when you add the broth. Just make sure the farro is cooked through before you add the spinach and basil - it may add on a few minutes of cooking time. If you only have fully uncooked farro, boil it separately according to the package instructions, then add it to the soup at the end.