In a small pan, gently heat the wine. Remove from the heat, add the saffron and let steep.
In a large pot, heat the oil over medium heat. Add the onions, fennel and garlic and cook, stirring, until soft, about 6 minutes. Add the tomatoes and cook, stirring, for 1 minute. Add the Herbsaint, increase the heat, and cook for 1 minute. Add the potatoes, salt, pepper, and chopped fennel fronds and stir well. Add the stock and saffron mixture and bring to a boil. Lower the heat and simmer until the potatoes are just tender but still firm, 5 to 6 minutes. Add the fish according to size and firmness and simmer until just cooked through, 4 to 5 minutes. Remove from the heat and adjust the seasoning, to taste.
To serve, ladle the soup into large soup bowls and garnish with chopped parsley. Place 2 rouille croutons on each serving and serve. Pass additional croutons and rouille in a bowl at the table, as desired.
Preheat the oven to 400 degrees F.
Smash 1 garlic clove with the back of a knife. Chop the remaining 3 cloves.
Place the bread slices on a baking sheet and rub the top side of each with the smashed garlic. Bake until light brown, about 8 minutes.
Remove from the oven and cool slightly.
In a food processor or blender, process the egg yolks for 10 seconds. Add the chopped garlic, lemon juice, cayenne, and salt and process to blend. With the machine running, in a steady stream add the oil and process until emulsified, thinning as necessary with the cooled bouillabaisse liquid. Adjust the seasoning, to taste.
To serve, place a large dollop on each crouton and place in the soup.
Yield: about 8 (1 cup) servings
