Prep / Total time : 1 hour makes 4 servings
2 tablespoons extra-virgin olive oil
1 small shallot, minced (1/4 cup)
1/4 cup minced parsley
6 garlic cloves, thinly sliced
**Few pinches of crushed red pepper**
1 head of escarole (1 pound), trimmed and chopped
1 bunch kale (1 pound)—stems and ribs discarded, leaves thinly sliced
1 bunch Swiss chard (1 pound)—stems and ribs discarded, leaves thinly sliced
8 cups chicken stock or low-sodium chicken broth
2 tablespoons unsalted butter, at room temperature
6 1-inch-thick, diagonal slices of baguette
2 tablespoons sherry vinegar
**Freshly ground white pepper**
1/2 cup freshly grated Parmigiano-Reggiano cheese
1 . In a large pot, heat the oil. Add the shallot, parsley, garlic and crushed red pepper. Cook over moderate heat, stirring, until fragrant, about 2 minutes. Add the escarole, kale and chard and cook, stirring, until the greens start to wilt, about 2 minutes. Add the stock and bring to a boil. Simmer until the greens are tender, about 20 minutes.
2 . Meanwhile, spread the butter on both sides of the bread slices. Heat a large nonstick skillet. Add the baguette slices and toast over moderate heat until golden, 2 to 3 minutes per side.
3 . Stir the vinegar into the soup and season with sea salt and white pepper. Ladle the soup into bowls, top with the toasts and garnish with the grated cheese.