2 tablespoons grapeseed oil
1 pound prosciutto, finely chopped (see Test Kitchen Note below)
1 medium yellow onion, roughly chopped
8 cups water
4 cups vegetable broth
One 28-ounce can diced tomatoes (preferably San Marzano)
1 whole bone-in, skin-on chicken breast (about 2 pounds)
6 cups fresh basil leaves (about 6 ounces)
1 teaspoon celery seeds
1 teaspoon fennel seeds
2 whole white peppercorns
1 cup Carnaroli or Arborio rice
2 tablespoons extra-virgin olive oil, plus more for serving
2 small carrots, finely chopped
¼ medium fennel bulb, cored and finely chopped
3 garlic cloves, thinly sliced
1½ cups cooked beans (such as black-eyed peas or cranberry beans)
½ teaspoon kosher salt
½ teaspoon freshly ground black pepper
2 cups coarsely chopped spinach or Swiss chard
1 cup thinly sliced kale (preferably Lacinato)
½ bunch fresh basil leaves, roughly chopped
Parmigiano-Reggiano cheese, finely grated on a Microplane
1. Make the broth: In a large stockpot set over medium heat, add the grapeseed oil. Add the prosciutto and onion and cook, stirring occasionally, until the prosciutto is browned and the onion is soft, about 8 minutes. Pour in the water and broth, add the tomatoes and bring to a simmer. Add the chicken and reduce the heat to low. Cover the pot and simmer for 45 minutes.
2. Uncover the pot and continue to simmer for another 20 minutes. Remove the pot from the heat and stir in the basil leaves, celery seeds, fennel seeds and white peppercorns. Set aside to steep for 30 minutes. Remove the chicken from the broth and transfer the meat to a cutting board. Remove and discard the skin, then use 2 forks to shred the meat (discard the bones). Strain the broth through a fine-mesh sieve and return the strained broth to the pot.
3. Make the soup: Add the rice to the pot and bring the broth to a simmer over medium-high heat. Cook until the rice is tender, about 25 minutes.
4. In a separate large pot set over medium heat, add the olive oil, carrots, fennel and garlic and cook, stirring occasionally, until the vegetables are soft, about 8 minutes. Add the beans and pour in the broth-rice mixture. Stir to combine.
5. Just before serving, season with the salt and pepper. Stir in the spinach, kale, chopped basil and the reserved pulled chicken. Heat until the chicken is warmed through, then divide the soup among bowls. Serve the soup with a drizzle of olive oil and a sprinkle of Parmigiano-Reggiano cheese.
Test Kitchen Note: Italian markets, gourmet shops, or the deli counter at the supermarket often sell prosciutto ends, the last elbow of prosciutto left from a leg, at a discounted cost.