- 3/4 cup mayonnaise
- 2 teaspoons Dijon mustard
- 2 teaspoons red wine vinegar
- 2 garlic cloves, minced
- 3/4 teaspoon hot pepper sauce
- 6 tablespoons olive oil
- 4 leeks (white and pale green parts only), sliced
- 2 carrots, cut into 1/2-inch pieces
- 1 fennel bulb, cut into 1/2-inch pieces
- 2 shallots, chopped
- 6 large garlic cloves, chopped
- 2 plum tomatoes, coarsely chopped
- 2 tablespoons tomato paste
- 1/2 teaspoon dried thyme
- 1/4 teaspoon saffron threads
- 1 1/2 cups dry white wine
- 5 cups (or more) chicken stock or canned low-salt chicken broth
- 3 pounds assorted fish fillets (such as sea bass, snapper, and orange roughy), cut into 2-inch pieces
- 1 French bread baguette, cut into 1/3-inch-thick slices, toasted
- Chopped fresh parsley
- Whisk first 5 ingredients and 3 tablespoons oil in small bowl to blend. Season to taste with salt and pepper. (Aioli can be made 1 day ahead. Cover and refrigerate.)
- Heat remaining 3 tablespoons oil in heavy large pot over medium heat. Add leeks, carrots, fennel, and shallots; sauté until golden brown, about 15 minutes. Add garlic and sauté 2 minutes. Mix in tomatoes, tomato paste, thyme, and saffron. Add wine and boil 5 minutes. Add 5 cups stock and bring to boil. Reduce heat and simmer 15 minutes to blend flavors. Add fish and simmer until fish is cooked through, about 5 minutes. Cool slightly.
- Working in batches, puree soup in blender. Working in batches, strain soup through coarse sieve set over large bowl, pressing firmly to force as much of solids as possible through sieve. Return soup to pot. Season to taste with salt and pepper. (Can be made 1 day ahead. Cover and chill.)
- Spread enough aioli over each toast to cover. Bring soup to simmer, thinning with more stock, if desired. Ladle soup into bowls. Top each with 2 toasts. Sprinkle with parsley and serve.