Year after year, this is the soup that my friends ask me to make for our holiday dinner. I'm glad to oblige, although the fish shop in my Italian-American neighborhood is packed on Christmas Eve morning. If you can, buy whole fish (a two-pound fish will yield about one pound of filets). Ask the fish store clean and filet them, and turn the bones and head into a fish stock.

3 tablespoons extra virgin olive oil
1 large onion, chopped
1 small fennel bulb (about 9 ounces), fronds trimmed, chopped
3 garlic cloves, chopped
1 1/2 cups dry white wine
6 cups homemade fish stock (recipe follows) or bottled clam juice
1 28-ounce can peeled tomatoes in juice, drained with juices reserved, and chopped
3 tablespoons chopped fresh parsley
1 1/2 teaspoons dried thyme
3/4 teaspoon dried savory or oregano
1/2 teaspoon salt
1/4 teaspoon fennel seed, crushed
1/4 teaspoon crushed hot red pepper flakes
1 pound striped bass filets, skinned, cut into 1-inch pieces
1 pound red snapper filets, skinned, cut into 1-inch pieces
1 teaspoon crushed saffron threads
8 slices crusty French or Italian bread, toasted
Freshly grated Parmesan cheese

Aïoli

1 large egg, at room temperature, or 1/4 cup liquid egg substitute
4 garlic cloves, crushed through a press
1 teaspoon fresh lemon juice
1/4 teaspoon crushed saffron threads
1/4 teaspoon salt
1/4 teaspoon hot red (cayenne) pepper
3/4 cup olive oil (not extra virgin)
3/4 cup vegetable oil

1. In a soup pot. heat the oil over medium heat. Add the onion and fennel bulb. Cook, stirring often, until the onion is translucent, about 8 minutes. Add the garlic and cook until fragrant, about 2 minutes.

2. Add the wine and bring to a boil. Add the stock, the tomatoes with their juices, parsley, thyme, savory, salt, fennel seed, and hot pepper. Bring to a simmer. Reduce the heat to low and simmer to blend the flavors, about 1 hour. (The soup base can be prepared up to 1 day ahead. Cool, cover, and refrigerate. Bring to a boil before continuing.)

3. Add the fish and saffron and bring to a boil over high heat. Cook until the fish is cooked through, about 5 minutes. Using a slotted spoon, transfer the solids (fish and vegetables) to a blender and food processor and blend with small amounts of the cooking liquid until puréed. Stir the purée back into the cooking liquid.

4. While the soup is cooking, make the aïoli: In a blender, combine the egg, garlic, lemon juice, saffron, salt and cayenne. In a glass measuring cup, combine the olive and vegetable oils.
5. With the motor running, slowly add the oils to the egg mixture, blending until thickened (it should take about 1 minute to add the oils). Cover and refrigerate until ready to serve.
6. To serve, place a piece of toast in the bottom of each bowl. Spoon the soup into the bowls. Pass bowls of the grated cheese and aïoli on the side.