Mediterranean Seafood Stew

Cut root ends from leeks. Cut each leek lengthwise in half, then into 1/4-inch-thick slices. Place in large bowl of cold water. With hands, swish leeks to remove grit. Repeat process, changing water several times. Drain. Transfer leeks to 6-quart slow cooker bowl along with fennel, tomatoes, garlic, 1 teaspoon salt, and 1/2 teaspoon freshly ground black pepper. With kitchen twine, tie thyme and parsley stems together. Bury in vegetable mixture. Cover with lid and cook on high 3 hours. Stir in mussels and shrimp, and lay fish on top. Immediately cover and cook 30 to 40 minutes longer or until mussels open and shrimp and fish turn opaque throughout. Divide mussels among serving dishes. Discard herb bundle. Transfer 3 cups stew to container; refrigerate overnight. Divide remaining stew among serving dishes. Drizzle oil over stew. Chop reserved parsley leaves and sprinkle over stew. Serve with rolls.