4 cloves garlic, peeled and smashed slightly with the side of chef’s knife, plus 1/2 head minced garlic
3 ounces fish liver (if using, try monkfish liver), optional
One 6-inch piece baguette (or a similar amount of another crusty bread), cut into 1/2-inch cubes
One 14-ounce can crushed tomatoes
1 cup white wine
1/2 cup brandy
3 pounds russet potatoes (about 4 large), peeled and cut into 1-inch chunks
2 quarts fish stock
2 teaspoons salt, plus more to taste
2 pounds white fish, skin removed and flesh cut into 2-inch chunks
In a large stock pot, heat 1/4 cup of the olive oil over medium heat. Fry the 4 smashed garlic cloves in the oil until deep golden brown. Remove the garlic from the oil using a spider or slotted spoon and set aside in a mortar and pestle.
If using, add the liver to the oil and fry until golden brown on all sides and slightly firm in texture, about 1 minute on each side.
After the liver, or if omitting, add the baguette chunks to the oil, adding more oil if necessary to keep the pan from drying out. Brown the baguette chunks, tossing occasionally, until deep golden brown and crispy, about 3 minutes. Transfer the fried bread to the mortar and pestle. If your mortar and pestle isn’t big enough to fit all of the ingredients, grind the fried garlic, bread and liver into a paste in batches. Set aside this mixture, called a “picada,” which will be used to thicken and flavor the stew.
Add the remaining 1/4 cup olive oil to the same stock pot. Add the minced garlic and cook until it’s a deep, rich nutty brown. Add the crushed tomatoes and cook until all the liquid has evaporated and the tomatoes have a jammy texture and are dark and caramelized.
Deglaze the pan with white wine and brandy. Bring to a simmer and reduce until the liquid has almost evaporated. Add the potatoes and salt, then cover with the fish stock. Bring the liquid to a boil, then simmer until the potatoes have softened and fall apart easily when pierced with a fork, 10 to 15 minutes.
Add the chunks of fish and cook until just cooked through, 1 to 3 minutes. Remove from the heat and stir in the picada.
Taste the stew for seasoning, adding salt if necessary. Serve immediately.