1 Cook the onions, leeks, fennel: Heat 1/4 cup of olive oil in a large (6-8 quart) pot on medium high heat. When the oil is hot, add the onions, leeks, and fennel. Stir to coat the vegetables with the olive oil. Cook on medium heat until softened but not browned, about 10-15 minutes.
2 Add garlic, tomatoes, bay leaf, thyme saffron, salt, orange zest: Add the crushed garlic, chopped tomatoes, bay leaf, thyme, saffron, salt, and orange zest.
Cook until the tomatoes are soft and broken down, about 10 more minutes.
3 Add fish fillets, cover with water and stock, boil: Cut fish fillets into 2-inch pieces. Bring 2 cups of water to a boil. Lay the fish pieces over the vegetable mixture and pour over with 2 cups of boiling water. Add clam juice or fish stock. Bring everything to a boil, and cook, uncovered, for about 5 minutes.
4 Add shellfish: Add the mussels, squid, and/or crab, pushing aside the fish so that the shellfish is now covered in liquid, and boil for 10 minutes more, uncovered.
Add freshly ground black pepper, and more salt to taste. Remove the bay leaves, sprigs of thyme, and orange zest from the broth.
5 Place slice of bread in bowl, top with rouille, then broth, then fish and shellfish: To serve, remove the fish and shellfish to a platter to keep warm. Place a thick slice of crusty French bread (plain or lightly toasted) in each bowl and put a dollop of the rouille sauce on top of the bread.
Ladle the soup broth over the bread, and then portion out fish and shellfish onto the bowls.