Marinate fish fillets with olive oil, saffron, garlic, thyme, and pepper for 2 hours in the fridge.
Soften onion, carrot, and fennel in olive oil over medium heat until tender.
Add thyme, bay leaf, garlic, and tomatoes, then stir in the saffron powder.
Heat white wine in a separate pan until bubbling, then remove from heat.
Add wine and tomato purée to the vegetables and cook for 3 minutes.
Incorporate fish bones and enough water to cover them into the pan.
Simmer the mixture for 30 minutes while skimming the surface regularly.
Blend the soup in batches and strain through a fine sieve into a clean pan.
Poach marinated fish in the soup and add a dash of pastis.
Whisk egg yolks and garlic, then slowly emulsify with olive oil and spices for the rouille.
Serve soup topped with rouille, croutons, grated cheese, and parsley.