How to Make It
In a large pot, heat 1 tablespoon of the olive oil until shimmering. Add the onion, fennel, potato, celery, garlic, leek tops, tomato and ginger and cook over moderate heat, stirring occasionally, until softened, 10 minutes.
Scrape the vegetables to one side of the saucepan and add the remaining 2 tablespoons of oil to the opposite side. Add the coriander, fennel seeds, star anise and bay leaf to the oil and cook, stirring, until fragrant, about 1 minute. Stir in the wine, salt, crushed red pepper and 8 cups of water and bring to a boil. Simmer over moderately low heat, stirring occasionally, until the vegetables are very tender, 20 to 25 minutes.
Strain the broth through a sieve into a clean saucepan, pressing the vegetables to extract the liquid. Discard the vegetables.