Heat olive oil in a large pot over medium heat.
Add onion, garlic, carrots, celery, and fennel. Sauté for 5–7 minutes until softened.
Stir in diced tomatoes, fish stock, white wine, saffron, salt, and pepper. Simmer for 10 minutes.
Add the fish chunks and cook for 5 minutes.
Add mussels, clams, and shrimp. Cover and cook for 5–7 minutes, or until shells open and shrimp turn pink. Discard any unopened shells.
Step 2: Make the Creamy Rouille Sauce
In a bowl, whisk the egg yolk with Dijon mustard, garlic, paprika, cayenne, and lemon juice.
Slowly drizzle in olive oil while continuously whisking until the mixture emulsifies into a creamy sauce.
Season with salt and pepper to taste.
Step 3: Serve
Ladle the seafood pot into bowls.
