Ingredients

• 1/2 cup (120ml) extra-virgin olive oil
• 1 large yellow onion (12 oz, 340g), diced
• 1 large leek (1 lb, 450g), washed and diced
• 1 medium fennel bulb (8 oz, 225g), cored and diced
• 5 medium garlic cloves, crushed
• 1/2 teaspoon whole fennel seeds
• 2 large pinches saffron threads
• 1 (2-inch) strip orange zest
• Large pinch cayenne pepper (or red chilli powder)
• 2 sprigs thyme
• 2 tablespoons (30ml) tomato paste
• 6 plum tomatoes (1 1/4 lb, 565g), cored, seeded, and diced
• 2 lb (900g) whole fish or fish bones and heads
• 2 cups (475ml) dry white wine
• 1/4 cup (60ml) Pernod or pastis (optional)
• 2 quarts (1.9L) boiling water (or as needed)
• 2 sprigs fresh flat-leaf parsley
• 1 bay leaf
• 2 medium garlic cloves
• 1/4 cup crumbled stale bread or panko breadcrumbs (1/2 oz, 15g)
• Large pinch cayenne pepper (or red chilli powder)
• Pinch saffron threads
• 1 large egg yolk
• Kosher or sea salt
• 1/2 cup (120ml) extra-virgin olive oil
• 3–5 lb mixed whole and/or filleted fish
• 1 lb mussels and/or crabs (optional)
• Baguette toasts, for serving

The broth

In a large saucepan, heat olive oil over medium heat.
Add onion, leek, fennel, garlic, fennel seeds, saffron, orange zest, cayenne, and thyme; cook until soft (about 10 minutes).
Stir in tomato paste; cook 2 minutes, then add diced tomatoes and cook 3 minutes.
Add fish (or fish bones/heads), white wine, and Pernod (if using); boil for 3 minutes.
Pour in boiling water to cover, add parsley and bay leaf, bring to a vigorous boil for 5 minutes, then simmer for 45 minutes. Season with salt and pepper.

The rouille

In a mortar and pestle, blender, or food processor, combine garlic, bread (or panko), cayenne, saffron, and egg yolk to form a paste.
Add 2 tablespoons of fish broth to thin slightly.
Drizzle in olive oil slowly until the mixture is thick and creamy. Season with salt and refrigerate until needed.

Blend

In batches, blend the broth and all solids until smooth (remove any hot splashes by covering the blender loosely).
Strain the blended broth through a fine-mesh strainer, pressing out all liquid and discarding bones and fibers.
Season the strained broth with salt and pepper.

Serve

Bring the strained broth to a gentle simmer.
Add whole and filleted fish; poach until just cooked. If using, add mussels or crabs and cook until done.
Transfer the fish to a serving platter.
Serve the broth alongside, with toasted bread, spread with the rouille.