Florentine Onion Soup with Walnuts

Ingredients

• 4 tablespoons extra-virgin olive oil
• 6 whole large yellow onions
• 6 cups vegetable broth
• 2 tablespoons aged balsamic vinegar
• ½ cup whole raw walnuts
• 3 whole anchovy fillets in oil, drained
• 2 whole fresh thyme sprigs
• 1 whole bay leaf
• ½ teaspoon sea salt
• ¼ teaspoon freshly ground black pepper
• 4 slices day-old country bread, sliced

Instructions

1. 1

   Slice each of the 6 large yellow onions in half, then slice lengthwise into half-moon pieces about 1/4-inch thick — you want them uniform so they caramelize evenly. You should have about 10 cups of sliced onions.

2. 2

   Toast 0.5 cup of raw walnuts in a dry 8-inch skillet over medium heat, shaking the pan occasionally, until fragrant and lightly browned, about 4-5 minutes. Transfer to a cutting board and coarsely chop when cool enough to handle.

3. 3

   Pat the 3 anchovy fillets with paper towels to remove excess oil, then finely chop them into a paste — you should end up with about 1 tablespoon of minced anchovy.

4. 4

   Pour 4 tablespoons of extra-virgin olive oil into a 5-quart Dutch oven or heavy-bottomed pot and set over medium heat. When the oil shimmers, add all of the sliced onions — they will seem like too much, but they will collapse dramatically as they cook.

5. 5

   Stir the onions frequently with a wooden spoon, scraping up any browned bits from the bottom of the pot. After about 10 minutes, the onions will begin to release their moisture and soften. Continue cooking, stirring every 2-3 minutes, until the onions are deeply golden brown and almost melting, about 25-30 minutes total. You're looking for caramelization, not charring — if they brown too quickly, lower the heat to medium-low. The kitchen should smell sweet and slightly nutty.

6. 6

   Once the onions are caramelized, add the chopped anchovy paste and the chopped toasted walnuts. Stir for 1 minute, breaking up the anchovy as it melts into the oil — this enriches the broth with umami depth.

7. 7

   Pour in 6 cups of vegetable broth, then add 2 tablespoons of aged balsamic vinegar, 2 fresh thyme sprigs, and 1 bay leaf. Bring to a gentle simmer over medium heat, then reduce heat to medium-low and simmer for 12-15 minutes, allowing the flavors to meld. The broth should taste complex — sweet from the onions, tangy from the vinegar, salty and deep from the anchovy, and slightly earthy from the walnuts.

8. 8

   Taste the soup and season with 0.5 teaspoon of sea salt and 0.25 teaspoon of freshly ground black pepper. Adjust balsamic or salt to balance the flavors — it should feel both comforting and sophisticated.

9. 9

   While the soup finishes simmering, toast the 4 slices of day-old country bread in a 425°F oven or over a gas flame until golden and slightly crisp, about 3-4 minutes per side.

10. 10

    Remove the thyme sprigs and bay leaf from the soup using a slotted spoon. Ladle the soup into four warm bowls, making sure each serving has plenty of caramelized onions and broth. Place one toasted bread slice in the center or on the rim of each bowl. Drizzle very lightly with additional extra-virgin olive oil if desired, and serve immediately while the soup is hot and the bread still has a crisp edge.

Tools you’ll need

• 8-inch skillet
• 5-quart Dutch oven or heavy-bottomed pot
• wooden spoon
• slotted spoon
• soup ladle
• cutting board
• chef's knife
• soup bowls

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