How to Make It
In a large soup pot, heat the olive oil until shimmering. Add the onion, leek, carrot and crushed red pepper, season with salt and cook over moderately high heat, stirring occasionally, until just tender, about 3 minutes. Stir in the celery root, rutabaga and sugar. Add the broth, tomatoes and 1 quart of water and bring to a boil, then reduce the heat to moderately low, cover and simmer until the rutabaga is tender, about 15 minutes.
Add the beans, celery rib and garlic and simmer for 5 minutes. Add more water if the soup is too thick. Stir in the basil, cheese and vinegar, season with salt and pepper and serve.