Soupe de Poisson(pronounced soup du pua-sohn) literally means "fish soup" in French, but in the US, it generally refers to Soupe de Poisson à la Sétoise, or fish soup in the style of Sète. Unlike its more well known sibling Bouillabaisse, Soupe de Poisson does not include any pieces of seafood and is more like a bique in that regard.
This isn't a dish to make when you're pressed for time, but with about a dollar's worth of scraps from the fishmonger and a little love, you'll be treated to a Soupe de Poisson that's brimming with briny nuanced umami without so much as a hint of fishiness. Because the soup is strained and pressed before serving, it has a rich velvety texture from the collagen in the fish, making the soup taste almost creamy. The tomatoes lend a balancing sweetness and acidity while the anise notes from the fennel and savory saffron bring out the best characteristics of the fish. Together with crisp pieces of grilled bread slathered with rouille, Soupe de Poisson makes for a beautiful brunch alongside a salad, with plenty of crisp grilled bread slathered with Rouille.
There are a couple tricks that I've picked up over the years that I've employed, to take this soup to the next level. The first is to clean the heck out of the fish (in the photo above the half on the left has been properly cleaned). Basically anything even remotely resembling blood should be scrubbed, scraped and washed out of the all the parts of the fish before you cook it. That's because the blood can taste bitter and have a fishy taste, both of which we don't want in our soup.
The second trick is to cure and then roast the fish before adding it to the soup. This does a couple of things. The curing step, reduces the water content of the fish, concentrating its umami producing amino acids. The roasting step takes advantage of the Maillard Reaction to rearrange those amino acids into thousands of new flavor compounds, adding depth to the soup. The roasting also renders out most of the fat in the skin and meat, which is a good thing for the soup, because the oils in the fish can also have a fishy taste.
The cooked soup gets passed through a strainer to remove the solids, which would normally be discarded, but I like to add water to the strained solids and briefly cook it, before straining, to extract every last bit of flavor before discarding.
As for the type of fish, you can use whole gutted fish, but I like using the trimmings from fish that have been filleted because you tend to get more flavor, as well as richness adding collagen from the bones and connective tissue. I've used the trimmings from Red Sea Bream, but any umami rich-fish such as Branzino (a.k.a. Loup de Mer), Horse Mackerel, or Red Snapper will work.
- 1 day before you plan to make the soup, thoroughly wash the fish bones using a spoon and clean brush to scrape away any clotted blood and remaining organs under cold running water. Thoroughly dry the fish and then set the pieces on a stainless steel wire rack set on top of an oven-safe tray.
- Sprinkle the fish evenly on all sides with the salt and then leave it uncovered in the refrigerator for 24 hours.
- When you're ready to make the soup, preheat the oven to 450 degrees F. Drain any excess water that's dripped off the fish from the tray and roast the fish on the rack until golden brown 15-20 minutes.
- While the fish is roasting, add the olive oil, onions, celery, fennel and garlic to a large heavy bottomed pot and saute over medium heat until lightly browned and starting to caramelize (about 20 minutes).
- Add the fennel seeds and saute until fragrant (another minute or two).
- Deglaze the pan with the white wine, scraping any browned bits off of the bottom of the pan. Boil the mixture until it no longer smells like alcohol.
- Add the water, tomatoes, thyme, parsley, and saffron. Add the roasted fish, partially cover and simmer for 1 hour, stirring occasionally to break up the pieces of fish.
- When the soup is done cooking, use tongs or chopsticks to pick any large thick bones from the soup that might damage your food processor, like pieces of the head and spine.
- Ladle the soup de poisson into a food processor and pulse 3-4 times until it's about the consistency of chunky salsa. Do not over process it.
- Pass the soup through a wire mesh strainer pressing firmly down on the solids to extract as much liquid as possible. You can also use a food mill if you have one.
- The solids should be very dry if you've pressed hard enough.
- Put the solids back in the pot along with 2 cups of water and bring the mixture to a boil. Pass the mixture back through a strainer, pressing on the solids to extract as much liquid as possible.
- Reheat the soup de poisson and finish by adjusting salt and pepper to taste and adding the Pernod. Serve and garnish with chopped parsley and grated Comté.