Bouillabaisse

In a large, heavy-bottomed stockpot over medium-high heat, heat the olive oil. Add the fennel, onions, and leeks and cover with a tight-fitting lid. Cook the vegetables, stirring occasionally, until just beginning to tenderize, about 5 minutes. Add the tomato and garlic, re-cover the pot, and continue cooking until the tomatoes begin to break down, 2 to 3 minutes. Add the tomato paste, cayenne, saffron, potatoes, fish stock, and bouquet garni. Season with salt and pepper and bring the liquid up to a boil. Cover the pot, reduce the heat to medium, and simmer until the potatoes are cooked, 10 to 15 minutes. Add the seafood in order of firmness and cooking time, with the denser fillets of fish going into the pot first, followed by shellfish and then shrimp. Simmer the soup, stirring very minimally to preserve the whole pieces of seafood, until the shellfish have opened and fish fillets have cooked through, 5 to 10 minutes total, depending on the seafood being used. To serve, remove and discard the bouquet garni. Carefully remove the fish and shellfish, arranging them on a large serving platter or in warm bowls. Ladle the broth and potatoes over fish and garnish with the herbs. Serve warm.