- 1 teaspoon kosher salt, plus ore for the pot
- 6 tablespoons extra-virgin olive oil
- 1 medium onion, sliced
- 2 garlic cloves, smashed and peeled
- 1 small fennel bulb, trimmed, halved, cored, and thinly sliced
- 6 anchovy fillets, shopped
- 1 medium head escarole, trimmed, leaves coarsely chopped
- ¼ teaspoon crushed red pepper flakes
- 1 pound spaghetti
- 2 tablespoons balsamic vinegar
- ½ cup freshly grated Grana Padano
Bring a large pot of salted water to a boil for the pasta. In a large skillet over medium-high heat, heat the olive oil, then add the onion and garlic. Cook until the onion is wilted, about 4 minutes. Add the fennel, and cook until it is wilted, about 4 minutes. Add the anchovies, and stir to dissolve them in the oil. Add the escarole, and season with the salt and crushed red pepper. Ladle in ½ cup pasta-cooking water, cover and cook until the escarole is tender, about 5 minutes.
Meanwhile, add the spaghetti to the boiling water. When the escarole is tender, uncover it, drizzle in the balsamic vinegar, and simmer to combine the flavors, just about 3 minutes.
When the pasta is al dente, remove with tongs and transfer directly to the simmering sauce. Toss to coat the pasta with the sauce, adding a little pasta water is it seems dry. Remove the skillet from the heat, remove the garlic, and sprinkle with the grated cheese. Toss, and serve immediately.