Heat a large saucepan over medium heat, melt the butter. Add the celery, carrots, onion, garlic, thyme and a generous pinch each of salt and pepper. Cook stirring occasionally, until the vegetables just start to soften, about 10 minutes. Sprinkle the flour over the vegetables and cook, stirring, until evenly coated and lightly browned, about 2 minutes.
Add the Bone Broth and water. Bring to a boil, then add the chicken. Bring to a boil again and add the farro. Simmer over moderately low heat, stirring occasionally, until the vegetables are tender, about 10 minutes. Season with salt and pepper to taste. Ladle the soup into bowls and serve.
High fives to our pal Molli Pletcher for this creative and easy dish.