Soupe de poison is more than just fish soup because its flavor embodies the true essence of the sea. It should have a strong fish flavor, a fair amount of heat from chilis, deep notes of saffron, and a hint of anise.
Heat the olive oil in the soup pot over medium heat. Then cook the onions and leeks until they are tender but not browned. This should take approximately 3 to 5 minutes.
Add the garlic and canned tomatoes, stir, and cook an additional 5 minutes.
Add 10 cups (2 1/2 quarts) of water, parsley, bay leaf, thyme, fennel, saffron, orange rind, pepper, salt, fish, shellfish, and parts.
Gently stir to combine and simmer uncovered for 40 minutes.
Carefully strain the soup into a large bowl. Gently press the liquid out of the seafood and herbs with a wooden spoon or spatula. Wipe the soup pot clean.
Return the fish broth to the soup pot, taste it, and correct the seasoning if needed by adding salt, pepper, or saffron.
Bring the soup to a boil and add the pasta and the peeled potato (for the rouille). Boil them until it is al dente, about 8 minutes.
After the potato is fork tender, pull it out and add it to the rouille sauce.
Put the croutons or toasted baguette slices in bowls and ladle the soup over them.
Garnish with fresh parsley or fennel fronds. Serve the cheese and rouille separately.
Put soft chopped red bell pepper, chili or Tabasco, potato, garlic, and basil into a food processor and blend on high until smooth.
Stir in olive oil until well combined.
Taste and season with salt and pepper.
Right before serving, thin sauce out with hot fish broth. Serve in a small bowl or sauceboat.